Chapter VI Diagnostics 6-1

Chapter VI Diagnostics01 ― Content of Chapter ........................................................................................................................6-102 ― Engine Diagnostics ........................................................................................................................6-103 ― Hydraulic Reservoir System Diagnostics ....................................................................................6-104 ― Conveyor Hydraulic Diagnostics ..................................................................................................6-405 — Trimmer/Auger Hydraulic Diagnostics .......................................................................................6-12

Charge Pump ............................................................................................................................6-12Pump Operation ........................................................................................................................6-13

06 ― Track Hydraulic Diagnostics .......................................................................................................6-1707 ― Lift Hydraulic Diagnostics ...........................................................................................................6-2408—Hydraulic Reservoir drawing .......................................................................................................6-2909—Rear Conveyor Hydraulic Drive Drawing .....................................................................................6-3010—Trimmer/Auger Drive Hydraulic Drawing .....................................................................................6-3111—Track Drive Hydraulic Drawing .....................................................................................................6-3212—Lift Pump Hydraulic Drawing ........................................................................................................6-3313—Machine Lift Hydraulic Drawing ...................................................................................................6-3414—Hitch/Lift Arms & Vibrator Hydraulic Drawing ............................................................................6-3515—Conveyor Lift Hydraulic Drawing .................................................................................................6-3616—Conveyor Swing Hydraulic Drawing ............................................................................................6-3717—Conveyor Fold Hydraulic Drawing ...............................................................................................6-3818—Case Drain/Lube Hydraulic Drawing ............................................................................................6-3919—Oil Cooler Hydraulic Drawing .......................................................................................................6-4020—Main Filter Hydraulic Drawing ......................................................................................................6-4121―Trimmer remote connections ........................................................................................................6-4322―Machine and Accessory CAN cables ...........................................................................................6-4423―Cable Assemblies ..........................................................................................................................6-4524―Left Slave Assembly ......................................................................................................................6-4625―Right Slave Assembly....................................................................................................................6-4726―Console Panel Assembly ..............................................................................................................6-4827―Master Controller Assembly .........................................................................................................6-4928―Operator Remote Assembly ..........................................................................................................6-5029―G+ Control Panel Assembly ..........................................................................................................6-5130―Accumulator Wiring Assembly .....................................................................................................6-5231―Hopper Remote Wiring Assembly ................................................................................................6-5332―Sensor Bulkhead Assembly ..........................................................................................................6-5433―Cat C11 Miscellaneous Wiring Assembly ....................................................................................6-5534―Engine Control Panel Assembly Tier IV .......................................................................................6-5635―Miscellaneous Wiring CAT Tier IV ................................................................................................6-57

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Chapter VI Diagnostics

01 ― Content of Chapter

This section gives procedures to follow in the event of a machine failure. Only the basic failures are covered in this section. For major failures, contact your nearest GOMACO distributor. Pay particular attention to all safety statements!

02 ― Engine Diagnostics

For diagnostic procedures on the John Deere or Caterpillar Diesel engine, refer to the appropriate Diesel Engine Manual.

03 ― Hydraulic Reservoir System Diagnostics

Hydraulic Reservoir

Lift Pump

To Left Track Motor

To Right Track Motor

To Trimmer/Auger MotorMain Filter

Left Track Pump

Rear Conveyor Pump

Sump Filters Reservoir

Right Track Pump

Transfer Conveyor Pump

Trimmer/Auger Pump

Pressure Tank

951326.eps

Pressure OilReturn OilDump or Drain

To Rear Conveyor Motor

To Transfer Conveyor Motor

The hydraulic reservoirs are contained within the main frame structure. Beginning at the tank, on the left side, the oil flow is routed through two, 100 wire mesh sump filters, with magnetic inserts, into the suction ports of the main hydraulic pumps. From the pumps, the oil is routed through the various circuits that power

the machine functions. Each circuit contains (a) relief valve(s) set to bypass at specific pressures. If a circuit should stall, the appropriate relief valve will open, bypassing oil.

Return oil from the various circuits is routed back to the tank at the front of the machine frame. The

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front tank is divided into two sections, with the back half being the pressure tank. The pressure tank is a sealed tank. The oil must flow through the main filter to get out of the pressure tank into the reservoir tank. The amount of pressure in the pressure tank will depend on the amount of pressure required to force the hydraulic oil through the main filter. This pressure is indicated on the filter pressure gauge. When the pressure reaches 25 psi (1.72 bar), the filter relief valve will open allowing unfiltered oil to be dumped into the system.

From the main filter, the oil flows along the front half of the front tank to the left reservoir tank. The oil then flows along the left tank back to the sump filters where the cycle repeats. Refer to the specification chapter for hydraulic oil capacity.

Symptom:

High main filter pressure.

Corrective Measures:

1. Clogged main filter. Remove and replace the main filter element as instructed in the Maintenance chapter.

2. Contaminated oil. If the filter must be replaced frequently, the oil may be contaminated and need to be changed. If water or diesel fuel has gotten into the oil, it must be changed. Refer to the Maintenance chapter for instructions on changing the oil.

3. Cold oil. If the hydraulic oil is extremely cold, it may cause high pressure. Allow the oil to warm up and recheck filter pressure.

Symptom:

Main pumps cavitate or aerate.


1. Low hydraulic oil level. Add the proper hydraulic oil to the reservoir to bring the level up to the full mark, with the oil cold. If a sight gauge is not present, add oil until it is 8 inches (205 mm) down from the top of the filler neck.

2. Sump filters clogged. Remove and clean the filters following the instructions given in the Maintenance chapter.

951477

3. Loose connections between the pumps and the hydraulic reservoir. Tighten all fittings, hose clamps and bolts securely. Check the O-ring on the pump inlet flanges for damage. Replace as necessary.

Symptom:

Oil flowing from the breather cap.


The hydraulic reservoir oil level is too high. The oil level should be at the full mark on the sight gauge or 8 inches (205 mm) down from the top of the filler neck, with the oil cold.

Symptom:

Hydraulic oil overheats.


1. Hydraulic oil level low. Check the reservoir oil level and add the proper oil to bring the level to the full mark with the oil cold.

2. Inlet filter clogged. Inspect the filter indicator and replace the filter as instructed in the maintenance chapter.

3. Air flow through the hydraulic oil cooler restricted. Clean the fins of the oil cooler. Check the fan belt tension. If the air flow through the oil cooler is restricted, the engine coolant temperature may also increase.

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951236

4. The in-line check valve before the oil cooler is stuck open, allowing the hydraulic oil to pass directly to the pressure tank instead of passing through the cooler. To check, compare the temperature of the check valve with the temperature of the inlet side of the oil cooler. If the oil cooler inlet temperature is lower than the check valve temperature, suspect that the check valve is at fault and replace it.

5. Relief valve open. If a hydraulic system is constantly stalling out, excessive heat is generated. Reduce the work load on the system to keep it from stalling. If a circuit is not being used, be certain the control valve is in the “off” position. If either conveyor system should stall, the oil from that system is dumped straight back to the pressure tank and does not go through the oil cooler. If both conveyor systems were to stall, all oil is routed directly back to the pressure tank, with no oil flow through the cooler.

6. Operating the system near relief setting with high ambient air temperature. Reduce the work load on the system to allow it to cool.

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04 ― Conveyor Hydraulic Diagnostics

High PressureCharge Pressure

Low Pressure ReturnCase Drain Return

Suction

Conveyor Hydraulic Circuit(Sauer Danfoss)

ConveyorDrive Motor

ConveyorPump

QuickDisconnects

SumpReservoir

Low PressureReservoir

PressureGauge

Charge Filter

951386a.eps

The oil flow for each conveyor drive system starts at the appropriate pump on the rear of the engine. Oil flow in each conveyor main circuit is in a continuous closed loop (hydrostatic). The quantity of oil flow is determined by pump speed and displacement while direction of flow is determined by the swashplate angle from neutral. The pump output, with the pump swashplate at maximum angle, for each conveyor system is 25 gpm (94.6 lpm) at 1850 rpm. The description for both conveyor drive systems is the same. A description of the closed loop hydraulic system operation is as follows.

Oil flows from the sump reservoir to the inlet of a charge pump mounted on the rear of each main pump which is driven at pump shaft speed. From the charge pump, the oil is routed to the charge filter before returning to the corresponding main pump. The purpose of the charge pump is; provide a flow of oil through the system for cooling purposes; supply oil under pressure to maintain a positive pressure

on the low pressure side of the main pump/motor circuit; provide sufficient oil under pressure for control purposes and for internal leakage makeup.

Note: Refer to the appropriate Sauer Danfoss pump service manual for more detailed description of the pump and location of the various valves.

Oil from the charge pump is directed to the low pressure side of the main circuit by one of two check valves. With the system in neutral, both check valves may be open, allowing oil from the charge pump into both sides of the system. When the system begins operation, one check valve will be held closed by the oil under high pressure. The opposite check valve (low pressure side) will be open, allowing the necessary oil into the system for cooling and for leakage makeup. The combination relief/check valves in the pump contain the charge check valves. For high pressure protection, a relief valve in the combination

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relief/check valve will limit the pressure to 3625 psi (250 bar) above charge pressure. 951186

Internal leakage built into the conveyor drive motor provides the proper cooling of the motor. An orifice fitting, built into the motor, provides a method of controlling the charge pressure level and also a means of removing the excess cooling oil added to the circuit by the charge pump. During periods of operation when the main pump is in neutral, excess oil from the charge pump is directed to the pump cooling circuit through the neutral charge relief valve in the charge pump. When operating in this condition, cooling flow is not admitted to the motor because it is at rest.

When the system is operated in the forward direction, high pressure oil is directed against one end of the shuttle spool causing it to shift, directing oil from the low pressure side to the flushing orifice. Excess cooling oil from the flushing orifice enters the motor case, then flows through a case drain line to the return manifold on the corresponding side. In this way the charge pump cooling oil is circulated through the motor to aid in cooling. If the system is operated in the reverse direction, high pressure oil is directed against the opposite end of the shuttle spool causing it to shift, directing oil from the low pressure side to the flushing orifice.

Control of speed and direction is accomplished by an electrical signal to the proportional EDC (Electrical Displacement Control) valve. The electronic signal to the EDC is provided by the controls on the control console. The pump swashplate is spring loaded to neutral position to insure positive neutral.

The swashplate in the pump is provided with a stroking piston to move the swashplate and thus vary pump displacement. Pressurizing one end of the stroking

piston while exhausting the other will move the swashplate from its neutral position. To obtain the reverse direction from neutral, the opposite end of the stroking piston is pressurized. The electrical signal sent to the EDC is converted to a magnetic field which acts on the control spool. Control oil is directed to the desired end of the stroking piston by the control spool. A feedback lever, connected to the stroking piston, maintains the pump flow for any given electrical signal within the control range.

If circuit pressures tend to overcome the swashplate-stroking piston preset position, the feedback linkage connecting the swashplate to the control spool will activate the spool and supply adequate pressure to the stroking piston to maintain the swashplate in its’ position. The control spool is spring centered and contains sufficient underlap to open both ends of the stroking piston to drain when the electronic signal is returned to center (null). This permits the stroking piston centering springs to move the swashplate to the zero stroke position insuring a positive neutral.

With no electrical signal supplied to the EDC, the swash plate in the pump returns to the neutral position. When the swash plate is in the neutral position, there is no pumping action, therefore no oil flow to the drive system. The corresponding conveyor will be stopped.

When a forward electrical signal is supplied to the EDC, the swash plate inside of the pump will begin to tilt and the pumping action will begin. The more current that is supplied to the EDC, the more the swash plate will tilt, increasing the oil flow. As the swash plate tilts, oil will be routed out a port on the pump, through a set of quick couplers, to an inlet port on the motor. As oil flows through the motor, it causes the shaft to turn, rotating the conveyor in the forward direction. Return oil from the conveyor drive motor is routed back to the pump through the opposite set of quick couplers.

When a reverse electrical signal is supplied to the EDC, the swash plate inside of the pump will begin to tilt in the opposite direction, causing the oil flow to the motor to be reversed. This will cause the conveyor to rotate in the reverse direction.

A line from the forward directional port on the pump is connected to the corresponding conveyor pressure gauge to monitor the system pressure. The pressure gauge will show pressure in the forward direction only.

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951397

Diagnostic procedures for the left and right conveyor drive systems are the same. A manual override lever on the EDC valve is provided to determine if the conveyor problem is electrical or hydraulic. By depressing the override lever in one direction, the corresponding conveyor should rotate forward, and should rotate in the reverse direction when the lever is depressed in the opposite direction. If the conveyor will rotate when the lever is operated, the problem is electrical. Refer to the conveyor electrical diagnostic section for appropriate electrical diagnostic procedures. If the conveyor will not rotate when the lever is operated, the problem is hydraulic. Use the following procedures to determine the problem.

Notice: Before performing any service work on the pump, make certain that the area surrounding the EDC Valve and the pump connections are thoroughly cleaned to prevent dirt from entering the pump. place plugs on or in open fittings to prevent contamination from entering the hydraulic system. It is recommended to use new gaskets and o-rings during reassembly.

Symptom:

Conveyor continues to turn with no electrical signal to the EDC valve.

Corrective Measures:951397

Make certain there are no electrical signals to the EDC by disconnecting the wires to it. If the conveyor stops, it is an indication that there is electrical signal supplied to the EDC valve. Follow the diagnostic procedures in the conveyor electrical diagnostic section to determine the cause of the signal. If the conveyor does not stop, proceed as follows:951401a

1. Manual centering spool not properly centered. Refer to the maintenance chapter, or the appropriate pump service manual, for procedures to follow for adjusting the spool to center.

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950894a

2. EDC valve is not properly centered. Refer to the maintenance chapter, or the appropriate pump service manual, for procedures to follow for adjusting the spool to neutral.

071-0574

Notice: The removal of any portion of the control mechanism may result in the loss of neutral, which will necessitate readjustment.

3. Electric displacement control (EDC) valve defective. The EDC valves are interchangeable from one pump to the other. However, the control spool (shown above) and the control sleeve (not shown) are a matched pair and must be interchanged as complete units with the EDC. If adjusting the spool centering will not correct the problem, swap the EDC valve. If the problem interchanges to the other conveyor system, replace the EDC valve and spool assemblies. Readjust the neutral position of the EDC valve.

Note: Refer to the appropriate Sauer-Danfoss pump service manual for more detailed instructions on the removal of the EDC valve.

4. Defective pump. If the system still will not return to neutral after replacing the control valve, replace the pump.

Note: When replacing a pump, lubricate the splines of the drive shaft with a high temperature grease before installation.

Symptom:

Conveyor will operate in one direction only.


Depress the manual override lever in either direction. If the conveyor will rotate when the lever is operated, the problem is electrical. Refer to the conveyor electrical diagnostic section for appropriate electrical diagnostic procedures. If the conveyor will not rotate when the lever is operated, the problem is hydraulic. Use the following procedures to determine the problem.071-0575

1. Defective charge check valve. Swap the combination relief/check valves in the pump. If the system now works in the opposite direction, one of the valves is defective and must be replaced. Refer to the pump service manual for more detailed procedures to follow for servicing the charge check valves.

2. Electric displacement control (EDC) valve defective. The EDC valves are interchangeable from one pump to the other. However, the control spool (shown above) and the control

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sleeve (not shown) are a matched pair and must be interchanged as complete units with the EDC. If adjusting the spool centering will not correct the problem, swap the EDC valve. If the problem interchanges to the other conveyor system, replace the EDC valve and spool assemblies. Readjust the neutral position of the EDC valve.

Note: Refer to the appropriate Sauer-Danfoss pump service manual for more detailed instructions on the removal of the EDC valve.

Symptom:

System response is sluggish.

Corrective Measures:D232

! !DANGER!Always engage the parking brake when leaving the operator platform. Stop the operation of the trimmer/auger and conveyors prior to leaving the operator platform. Severe injury or death can occur if personnel are caught in moving parts.

1. Check the charge pressure with the control module in the neutral position, and in the forward and reverse positions as described in the Maintenance chapter. If the charge pressure is low in neutral, inspect the charge relief valve in the pump. Adjust the charge relief valve as described in the Maintenance chapter. If adjustment does not solve the problem, interchange the charge relief valve to the pump for the other conveyor. If the problem switches to the other conveyor, replace the charge relief valve. If the problem remains on the same conveyor, refer to the following measures.

Refer to the appropriate pump service manual for more detailed procedures to follow for servicing the pump charge relief valve.

951187

2. If the charge pressure is low in forward or reverse, inspect the charge relief orifice fitting in the motor. Remove and clean the orifice fitting. Refer to the motor service manual for more detailed procedures to follow for servicing the motor charge pressure orifice fitting.

3. Defective charge pump. Disassemble the pump and inspect it for wear. If the pump shows excessive wear, or damage, replace it. Refer to the appropriate pump service manual for more detailed procedures to follow for servicing the charge pump.

Note: It may be necessary to remove some of the hydraulic oil from the reservoir before removing the charge pump.

4. If the preceding checks are satisfactory, suspect that the main pump has failed. Remove the pump and have it serviced at a repair center.


Symptom:

Conveyor will not turn, high pressure indicated.


Before checking the hydraulic system, make certain that the conveyor is not full of debris, binding it. Normal conveyor operating pressures range from 500 to 3500 psi (34 to 241 bar). Refer to the Maintenance chapter for correct pressure relief settings.

1. Quick coupler disconnected or defective. If the hydraulic lines become pressurized up to the quick couplers but not beyond, the quick couplers are disconnected or defective. Reconnect or replace the quick couplers as necessary.

2. Damaged motor. Remove the hydraulic motor and attempt to run it free. If it does not turn but hydraulic pressure is evident, the motor is defective and must be replaced.

Symptom:

Conveyor stalls at low pressure.


1. Low system pressure. If the problem occurs in one direction, interchange the check/relief

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valves to see if the problem changes to the other direction. Replace the check/relief if the problem changes to the other direction.

Note: The relief valves are factory set and should not be tampered with. Replace the entire cartridge.

2. Hydraulic motor allowing oil to leak internally, relieving system pressure. This is evident when the conveyor stalls at low pressure when attempting to operate it at low speed. To check, interchange the drive motor with the motor from the other conveyor. If the problem transfers, the motor is defective and must be repaired, or replaced.

3. If the problem remains on the same conveyor, suspect pump damage and refer to the appropriate pump service manual for more detailed service procedures.


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05 — Trimmer/Auger Hydraulic Diagnostics

The oil flow for the trimmer/auger drive system starts at the top pump on the rear of the engine. Oil flow in the trimmer/auger circuit is in a continuous closed loop (hydrostatic). The quantity of oil flow is determined by pump speed and displacement while direction of flow is determined by the swashplate angle from neutral. The pump output, with the pump swashplate at maximum angle is 100 gpm (378.5 lpm) for the 9000 and 130 gpm (492 lpm) for the 9500 at 1850 rpm. A description of the closed loop hydraulic system operation is as follows.

Oil flows from the reservoir to the inlet of a charge pump, mounted on the rear of the main pump, which is driven at pump shaft speed. From the charge pump, the oil is routed to the charge filter before returning to the main pump. The purpose of the charge pump is; to provide a flow of oil through the system for cooling purposes; to supply oil under pressure to maintain a positive pressure on the low pressure side of the main pump and motor closed loop circuit; to provide sufficient oil under pressure for control purposes; and to provide for internal leakage makeup.

Note: Refer to the appropriate pump service manual for a more detailed description of the pump and location of the various valves.

Charge Pump

Oil from the charge pump is directed to the low pressure side of the main circuit by means of one of two check valves. With the system in neutral, both check valves may be open, allowing oil from the charge pump into both sides of the system. When the system begins operation, one check valve will be held closed by the oil under high pressure. The opposite check valve (low pressure side) will be open, allowing the necessary oil into the system for cooling and for leakage makeup. The Sauer Danfoss multi-function valves in the pump contain the charge check valves. For high pressure protection, the Sauer Danfoss multi-function valves will limit the pressure to 4000 psi (345 bar) above charge pressure.

950931

A flushing relief valve (number 2 in photo), built into a manifold block between the pump and the motor, provides a method of controlling the charge pressure level and also a means of removing the excess oil added to the circuit by the charge pump.951454a

During periods of operation when the main pump is in neutral, excess oil from the charge pump is directed to the pump cooling circuit through the neutral charge relief valve (number 2 in photo) in the charge pump. When operating in this condition, cooling flow is not admitted to the motor because it is at rest.

When the motor is operated in one direction or the other, a shuttle spool in the flushing manifold will shift directing oil from the low pressure side of the circuit to the flushing relief valve (shown previously in photo number 950931a). Oil drained in this manner is directed to the return manifold and routed through the oil cooler.

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Pump Operation

Control of speed and direction is accomplished by an electrical signal to the pump electrical coils. The electronic signal to the electrical coils is provided by the controls on the console. The pump swashplate is spring loaded to neutral position to insure positive neutral.

The swashplate in the pump is provided with a stroking piston to move the swashplate and thus vary pump displacement. Pressurizing one end of the stroking piston while exhausting the other will move the swashplate from its neutral position. To obtain the reverse direction from neutral, the opposite end of the stroking piston is pressurized. The electrical signal to the coil is converted to a magnetic field which acts on the control spool. Control oil is directed to the desired end of the stroking piston by the control spool. A feedback lever, connected to the stroking piston, maintains the pump flow for any given electrical signal within the control range.

If circuit pressures tend to overcome the swashplate-stroking piston preset position, the feedback linkage connecting the swashplate to the control spool will activate the spool and supply adequate pressure to the stroking piston to maintain the swashplate in its’ position. The control spool is spring centered and contains sufficient underlap to open both ends of the stroking piston to drain when the electronic signal is returned to center (null). This permits the stroking piston centering springs to move the swashplate to the zero stroke position insuring a positive neutral.

Without electrical signal to the electrical coil, the swash plate in the pump returns to the neutral position. When the swash plate is in the neutral position, there is no pumping action, therefore no oil flow to the drive system. The trimmer will be stopped.

When a forward electrical signal is supplied to the electrical coil, the swash plate inside of the pump will begin to tilt and the pumping action will begin. As current is increased to the electrical coil, the swash plate will tilt more, increasing the oil flow. As the swash plate tilts, oil will be routed out a port on the pump, through a set of quick couplers, to a manifold. The manifold routes the oil flow to each inlet port of the drive motor(s) on the trimmerwheel. As oil flows through the motor, it causes the shaft to turn, rotating the trimmerwheel in the forward (undercutting) direction. Return oil from each trimmer drive motor is routed through the manifold and back to the pump through the opposite set of quick couplers.

When a reverse electrical signal is supplied to the electrical coil, the swash plate will begin to tilt in the opposite direction, causing the oil flow to the motor(s) to be reversed. This will cause the trimmerwheel or placing auger to rotate in the reverse direction.

A line from the forward directional port on the pump is connected to the trimmer pressure gauge to monitor the system pressure. The pressure gauge will show pressure in the forward direction only.

Note: A flow meter was added to the system in 2005. Refer to the trimmer electrical system for more information.

951424a

A manual override lever is provided on the pump to determine if the trimmer problem is electrical or hydraulic. By moving the override lever in one direction, the trimmer should rotate forward, and should rotate in the reverse direction when the lever is moved in the opposite direction. If the trimmer will rotate when the button or lever is operated, the problem is electrical. Refer to Troubleshooting the Trimmer Electrical Circuit for appropriate electrical troubleshooting procedures. If the trimmer will not rotate when the button is operated, the problem is hydraulic. Use the following procedures to determine the problem.

Notice: Before performing any service work on the pump, make certain that the area surrounding the control module and the pump connections is thoroughly cleaned to prevent dirt from entering the pump. Place plugs on/in open fittings to prevent contamination from entering the hydraulic system. It is recommended to use new gaskets and O-rings during reassembly.

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Symptom:

Trimmer continues to turn with no electrical signal to the proportional solenoid.


Make certain that there is no electrical signal to the pump controls by disconnecting the packard connector from the Sauer Danfoss pump. If the trimmer stops, it is an indication that there is electrical signal supplied to the control valve. Follow the procedures in the Trimmer Electrical Diagnostic section to determine the cause of the signal. If the trimmer does not stop, proceed as follows:951463a

2. Proportional control module (number 2 in photo) requires adjustment. Refer to the maintenance chapter, or the appropriate pump service manual, for procedures to follow when adjusting the spool to center.

950648

3. EDC valve defective. If adjusting the spool centering will not correct the problem, replace the EDC valve. Thoroughly clean the area around the module/valve prior to removal to prevent any contamination from entering the system. To remove the control module/valve, disconnect the electrical connectors. Remove the bolts and carefully extract the control module/valve and feedback lever from the pump case. Inspect the O-rings and gasket and replace them as necessary. When installing the control module/valve, make certain that the feedback lever extending from the control module/valve is properly engaged in the pump. Insert the bolts and tighten securely.

4. Defective pump. If after replacing the control module, the system still will not return to neutral, suspect the pump. It may be necessary to replace the pump.


Symptom:

Trimmer/Auger will operate in one direction only.


Move the manual override lever on the pump in both directions. If both directions operate normally the problem is electrical, refer to the Trimmer Electrical Diagnostic section for more information. If the problem remains the same, use the following procedures to determine the problem.

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950508

1. Defective shuttle spool. Remove the shuttle spool from the flushing manifold. The spool must move smoothly in the bore. Inspect and replace any worn, galled or broken parts. Reassemble and check the system for proper operation.

951479a

2. Defective relief valve. Swap the multi-function valves in the pump. If the system now works in the opposite direction, replace the defective valve. Refer to the pump service manual for more detailed procedures to follow when servicing the relief valves.

951454

3. Defective EDC coil. Swap the Sauer Danfoss packard connector to the secondary coil on the EDC valve. If the problem is corrected, the solenoid coil is defective and must be replaced. Operation may continue with one operating coil.

4. Defective pump. If the system will not operate after interchanging the control valve solenoid coils, suspect the pump. Replace or repair the pump.


Symptom:



1. Check the charge pressure with the controls in the neutral position, and in the forward and reverse positions as described in the Maintenance chapter. If the charge pressure is low in neutral, inspect the charge relief valve in the pump. Adjust or replace the charge relief valve as necessary. If the charge pressure is low in forward or reverse directions, inspect the flushing relief valve in the flushing manifold. Adjust or replace the flushing valve as necessary. Refer to the appropriate pump service manual for more detailed procedures to follow for servicing the pump charge relief valve.

2. Defective charge pump. Disassemble the pump and inspect it for wear. If the pump shows excessive wear, or damage, replace it. Refer to the appropriate pump service manual for more detailed procedures to follow for servicing the charge pump.

Note: It may be necessary to remove some of the hydraulic oil from the reservoir before removing the charge pump.



Symptom:

Trimmer or auger will not turn, high pressure indicated.

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Before checking the hydraulic system, make certain that the trimmerwheel or auger is not full of debris, causing it to bind. Normal trimmer operating pressures range from 500 to 3500 psi (34 to 241 bar). Refer to the Maintenance chapter for correct pressure relief settings.

1. Quick coupler disconnected or defective. If the hydraulic lines become pressurized up to the quick couplers but not beyond, the quick couplers are disconnected or defective. Reconnect or replace the quick couplers as necessary.

2. Damaged motor. Remove the hydraulic motor and attempt to operate it. If it does not turn but hydraulic pressure is evident, the motor is defective and must be replaced.

Symptom:

Trimmer or auger stalls at low pressure.


1. Low system pressure. Refer to Maintenance chapter for instructions on how to adjust trimmer pump pressure override relief valves and high pressure relief valves.

2. Defective hydraulic motor allowing oil to leak past rotor internally, relieving system pressure. This is evident when the trimmer or auger stalls at low pressure when attempting to operate it at low speed. To check, remove the case drain line and attach a short hydraulic line to the motor. Place the line in a suitable container and operate the trimmer or auger to check for leakage. If a large amount of hydraulic fluid is discharged under pressure, the motor is defective and must be replaced. If a small amount of hydraulic fluid is discharged (less than 0.5 gpm [1.9 lpm]), the motor is good.

Note: The Hägglunds motor is not equipped with a case drain line. Check outlet lube flow by disconnecting the inlet and outlet lines from the couplers at the front of the machine. Remove the coupler from the end of the motor outlet lube line and operate the trimmer wheel. Discharge the oil into a container for disposal. Repair or replace the motor if outlet lube flow exceeds 1 gpm (3.785 lpm).

3. Defective pump. Refer to the appropriate pump service manual for more detailed service procedures.


Symptom:

Oil leak at trimmer or auger drive motor or gearbox.


1. Defective motor shaft seal. If the motor shaft seal should rupture, external leakage will be apparent. Refer to the appropriate motor repair manual or the GOMACO Hägglunds seal replacement manual for repair procedures.

2. Excessive gear lube flow may cause motor seal failure. Connect a flow meter between the gear lube quick couplers on the front bulkhead. With the engine running, adjust the flow control valve to flow 6 gpm (22.7 lpm).

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06 ― Track Hydraulic Diagnostics951339

Return Manifoldto Oil Cooler

ConsolePressureGauge

Track BrakeSolenoidValve

HydrostaticTrack DrivePump

Track DriveMotor andGearbox

ChargeFilter

Track Hydraulic Circuit

951339a.eps

Low PressureReservoir

SumpReservoir

The oil flow for left track drive system starts at the front pump on the lower left corner of the gearbox on the rear of the engine (looking at rear of engine). The oil flow for right track drive system starts at the front pump on the lower right corner of the gearbox on the rear of the engine (looking at rear of engine). Oil flows in each track main circuit in a continuous closed loop (hydrostatic). The quantity of oil flow is determined by pump speed and displacement while direction of flow is determined by the swashplate angle from neutral. The pump output, with the pump swashplate at maximum angle, for each track system is 41.35 gpm (156.50 lpm) at 1850 rpm. The description for both track drive systems is the same. A description of the closed loop hydraulic system operation is as follows.

Oil flows from the sump reservoir to the inlet of a charge pump mounted on the rear of each main pump which is driven at pump shaft speed. From the charge pump, the oil is routed through the charge filter before returning to the corresponding main pump.

The purpose of the charge pump is; provide a flow of oil through the system for cooling purposes; supply oil under pressure to maintain a positive pressure on the low pressure side of the main pump/motor circuit; provide sufficient oil under pressure for control purposes and for internal leakage makeup.

Note: Refer to the appropriate Sauer Danfoss pump service manual for more detailed description of the pump and location of the various valves.

Oil from the charge pump is directed to the low pressure side of the main circuit by one of two check valves. With the system in neutral, both check valves may be open, allowing oil from the charge pump into both sides of the system. When the system begins operation, one check valve will be held closed by the oil under high pressure. The opposite check valve (low pressure side) will be open, allowing the necessary oil into the system for cooling and for leakage makeup. The multi-function valves in the

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pump contain the charge check valves. For high pressure protection, a relief valve in the multi-function valves will limit the pressure to 3625 psi (250 bar) above charge pressure. Refer to the 90 series pump service manual for more information on the multi-function valves.

Internal leakage built into the track drive motor provides the proper cooling of the motor. An orifice fitting, built into the motor, provides a method of controlling the charge pressure level and also a means of removing the excess cooling oil added to the circuit by the charge pump. During periods of operation when the main pump is in neutral, excess oil from the charge pump is directed to the pump cooling circuit through the neutral charge relief valve in the charge pump. When operating in this condition, cooling flow is not admitted to the motor because it is at rest.

When the system is operated in the forward direction, high pressure oil is directed against one end of the shuttle spool causing it to shift, directing oil from the low pressure side to the flushing orifice. Excess cooling oil from the flushing orifice enters the motor case, then flows through a case drain line to the return manifold on the corresponding side. In this way the charge pump cooling oil is circulated through the motor to aid in cooling. If the system is operated in the reverse direction, high pressure oil is directed against the opposite end of the shuttle spool causing it to shift, directing oil from the low pressure side to the flushing orifice.

Control of speed and direction is accomplished by an electrical signal to the proportional EDC (Electrical Displacement Control) valve. The electronic signal to the EDC is provided by the controls on the control console. The pump swashplate is spring loaded to neutral position to insure positive neutral.

The swashplate in the pump is provided with a stroking piston to move the swashplate and thus vary pump displacement. Pressurizing one end of the stroking piston while exhausting the other will move the swashplate from its neutral position. To obtain the reverse direction from neutral, the opposite end of the stroking piston is pressurized. The electrical signal sent to the EDC is converted to a magnetic field which acts on the control spool. Control oil is directed to the desired end of the stroking piston by the control spool. A feedback lever, connected to the stroking piston, maintains the pump flow for any given electrical signal within the control range.

If circuit pressures tend to overcome the swashplate-stroking piston preset position, the feedback linkage

connecting the swashplate to the control spool will activate the spool and supply adequate pressure to the stroking piston to maintain the swashplate in its’ position. The control spool is spring centered and contains sufficient underlap to open both ends of the stroking piston to drain when the electronic signal is returned to center (null). This permits the stroking piston centering springs to move the swashplate to the zero stroke position insuring a positive neutral.

With no electrical signal supplied to the EDC, the swash plate in the pump returns to the neutral position. When the swash plate is in the neutral position, there is no pumping action, therefore no oil flow to the drive system. The corresponding track will be stopped.

When a forward electrical signal is supplied to the EDC, the swash plate inside of the pump will begin to tilt and the pumping action will begin. The more current that is supplied to the EDC, the more the swash plate will tilt, increasing the oil flow. As the swash plate tilts, oil will be routed out a port on the pump, through a set of quick couplers, to an inlet port on the motor. As oil flows through the motor, it causes the shaft to turn, rotating the track in the forward direction. Return oil from the track drive motor is routed back to the pump through the opposite set of quick couplers.

When a reverse electrical signal is supplied to the EDC, the swash plate inside of the pump will begin to tilt in the opposite direction, causing the oil flow to the motor to be reversed. This will cause the track to rotate in the reverse direction.

A line from the forward directional port on the pump is connected to the corresponding track pressure gauge to monitor the system pressure. The pressure gauge will show pressure in the forward direction only.

Symptom:

Chain frequently breaks or comes off.

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Corrective Measures:W64

WARNING!! !If the tracks are full of material that must be cleared by hand, the machine must be stopped and the engine must be shut off before clearing the material or serious injury, or death, can result if the machine were to move. Be certain that personnel are clear of the tracks before starting the engine or moving the machine. Do not stand on moving track. Do not operate the machine with the track guards (fenders) removed. Keep hands and feet clear of the tracks while in operation.

1. Debris in track chain. Clean track chain thoroughly and check links for rocks or hardened concrete.

2. Incorrect chain tension. Refer to the Maintenance chapter for instructions on the proper adjustment of the track chain.

Symptom:

Track continues to rotate with no electrical signal to the EDC valve.


Make certain that there is no electrical signal to the EDC valve by disconnecting the wires to it. If the track stops, it is an indication that there is electrical signal supplied to the EDC. Follow the diagnostic procedures in the Track Electrical diagnostic section to determine the cause of the signal. If the track does not stop, proceed as follows:

951475

1. Electric displacement control (EDC) valve spool not properly centered. Refer to the maintenance chapter, or the appropriate pump service manual, for procedures to follow when adjusting the spool to center.

053-0178

2. Pilot valve on EDC defective. Remove the pilot valve from the EDC and swap it with the pilot valve from the EDC on the opposite pump. If the problem swaps sides, the pilot valve is defective and must be replaced.

3. Electric displacement control (EDC) valve defective. If adjusting the spool centering will not correct the problem, interchange the EDC valves between the left and right track pumps. Thoroughly clean the area around the EDC prior to removal to prevent any contamination from entering the system. To remove the EDC, disconnect the electrical connectors. Remove the bolts and carefully extract the EDC valve and disengage the feedback lever. Inspect the o-rings and gasket and replace them as necessary. When installing the EDC, make certain that the feedback

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lever extending from the EDC is properly engaged in the pump. Insert the bolts and tighten according to specifications. If the problem affects the opposite track drive, replace the EDC valve.

Note: Refer to the Sauer-Danfoss pump service manual for more detailed instructions on the removal of the EDC valve.

4. Defective pump. If after swapping the EDC, the same system still will not return to neutral, suspect the pump. Repair or replace the pump.


Symptom:

Track runs slower than normal, but stalls at correct pressure.


Notice: Do not stall a system with an unknown relief pressure setting. If the pressure setting is too high, serious machine damage may occur. When checking a relief pressure setting, turn the adjustment screw out 3 or 4 turns before stalling the system.

1. A defective pump can cause the track to run slower than normal, yet stall at the proper relief pressure. The pump should be checked with a flow meter if available. A good indication of a defective pump is to compare relief pressure to engine speed. To check, disconnect both drive hoses at the quick couplers on both tracks. Place the forward/reverse switch in the "forward" position and the travel/neutral switch in the "travel" position. Start the engine and run it at 1000 rpm. Place the main control module in the "run" mode. Slowly rotate the variable speed dial in the increase direction and note the increasing pressure on the corresponding pressure gauge. If the pressure continues to increase above 4500 psi (310 bar), immediately move the travel/neutral switch to the "neutral" position. Readjust the pressure relief valve following the instructions in the Maintenance chapter. If the pressure does not increase above 4500 psi (310 bar), rotate the variable the maximum amount and increase the engine speed to maximum. Gradually reduce the engine speed while noting the pressure reading on the gauge. A damaged pump will not maintain relief pressure, but pressure will drop rapidly as engine speed is decreased. A good pump

will maintain approximately the same pressure regardless of engine speed. Repair or replace the pump as necessary, if found to be defective.

2. Engine is not operating at maximum speed (1850 rpm). If the engine speed is low, hydraulic pump output flow will be low, causing the tractive circuit, as well as all other hydraulic systems, to operate slower. Increase engine speed to maximum.

Symptom:

Track on one side will operate in one direction only.


1. Defective shuttle spool in the drive motor. The shuttle spool is an integral part of the current track drive motors. Remove and interchange the track drive motors between the left and right tracks. If the problem switches to the opposite track, the motor is defective and must be repaired or replaced.

951410a

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2. Defective multi-function valve. Interchange the multi-function valves in the pump. If the system now works in the opposite direction, the valve on the non-driving side is defective and must be replaced. Refer to the pump service manual for more detailed procedures to follow for servicing the relief valves.

3. Tow option is engaged. Turn the multi-function valve tow adjustment screw in until it stops to return to normal operation. The large adjustment nut on the multi-function valves serve as a tow option adjustment. Turning each screw out three turns will engage the tow option, causing the oil to bypass the pump so that the motors will freewheel for short distance towing. Adjust both cartridges in the left and right track pumps to allow towing.

Note: Hydraulic pressure must be applied to release the left and right track brakes in the track gearboxes prior to towing.

950648

4. EDC valve defective. Remove the Packard connector from the EDC valve coil. Remove the cap screws securing the EDC valve to the pump, and pull the valve away from the pump housing. Swap the suspect EDC with the opposite track pump. If the problem switches to the opposite track, replace the EDC valve.

5. Defective pump. If after interchanging the EDC valve, the system still will not operate in the one direction, repair or replace the pump.


Symptom:



WARNING!! !Contact with moving tracks can cause serious injury. Be certain that no one is near the tracks before moving them. Do not stand on moving track. Do not operate the machine with the track guards (fenders) removed. Keep hands, feet and loose clothing away from moving parts to prevent severe injury.

1. Check the charge pressure with the controls in the neutral position, and in the forward and reverse positions as described in the Maintenance chapter. If the charge pressure is low in neutral, inspect the charge relief valve in the pump. Adjust the charge relief valve as described in the Maintenance chapter. If adjustment does not remove the problem, interchange the charge relief valve to the pump for the other track. If the problem switches to the other track, replace the charge relief valve. If the problem remains on the same track, refer to the following measures. Refer to the appropriate pump service manual for more detailed procedures to follow for servicing the pump charge relief valve.

950502

2. Defective charge pump. Disassemble the pump and inspect it for wear. Replace the pump if it shows excessive wear or damage. Refer to the appropriate pump service manual for more detailed procedures to follow for servicing the charge pump.

Note: It will be necessary to remove some of the hydraulic oil from the reservoir before removing the pump for service.


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Symptom:

Machine will not travel straight when electrical controls are set for straight ahead.


First be certain that the electrical controls are set for straight ahead, then proceed as follows;W64

WARNING!! !If the tracks are full of material that must be cleared by hand, the machine must be stopped and the engine must be shut off before clearing the material or serious injury, or death, can result if the machine were to move. Be certain that personnel are clear of the tracks before starting the engine or moving the machine. Do not stand on moving track. Do not operate the machine with the track guards (fenders) removed. Keep hands and feet clear of the tracks while in operation.

1. Debris in track chain(s). Clean track chain(s) thoroughly and check links for rocks or hardened concrete.

2. Track tensions uneven. Be certain that both tracks are tensioned evenly. Refer to the Maintenance chapter for tensioning instructions.

3. Pump stroke controllers not set properly. Adjust the stroke controllers following the instructions in the Maintenance chapter.

216G+

Thresholds

2322

213G+

F N R

F N R

2322

2020

8080

▼

4. EDC calibration values not set properly. Calibrate the EDC drive values following the instructions in the Maintenance chapter.

Symptom:

Track on one, or both, side(s) will not turn, high pressure indicated.


Before checking the hydraulic system, make certain that the track is not full of debris causing it to bind. Normal track operating pressures range from 500 to 3500 psi (34 to 241 bar). Refer to the Maintenance chapter for correct pressure relief settings.

1. Damaged motor. Remove the hydraulic motor and attempt to run it free. If it does not turn but hydraulic pressure is evident, repair or replace the motor.

2. Damaged gearbox. If the problem remains on the same track, suspect the track drive gearbox. Remove the gearbox, dismantle it, and examine the gears, bearings and seals. Replace any parts if damage is evident. Refer to the appropriate gearbox disassembly brochure for procedures to follow. When installing the gearbox, torque the sprocket to gearbox attaching hardware to 435 ft. lb. (590 Nm).

Symptom:

Track stalls at low pressure.


1. Low system pressure. Refer to Maintenance chapter for instructions on how to adjust track multi-function valves.

2. Hydraulic motor allowing oil to leak internally, relieving system pressure. This is evident when the track stalls at low pressure when attempting to operate it at low speed. To check, interchange the drive motor with the motor from the opposite track. If the problem transfers, the motor is defective and must be repaired, or replaced.

3. If the problem remains on the same track, suspect pump damage and refer to the appropriate pump service manual for more detailed service procedures.


SYMPTOM:

Oil leak at track drive gearbox.

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CORRECTIVE MEASURES:

1. Defective mounting between the motor and gearbox. Remove the track drive motor and replace the ruptured seal.

2. Defective seal in the gearbox. This is evident by oil leaking from between the stub shaft and outer housing of the gearbox. Remove the gearbox and dismantle and replace the seal following procedures in the appropriate gearbox disassembly brochure.

3. Defective motor shaft seal. If the motor shaft seal should rupture, it may allow an excessive amount of oil into the gearbox, pressurizing the gearbox, causing the gearbox seal to fail. Remove the motor from the gearbox. Insert a tee fitting into the case drain line at the motor connection and connect a 3000 psi (207 Bar) pressure gauge. With the motor operating at maximum speed, the pressure should not exceed 75 psi (5.17 Bar). If the pressure exceeds this amount, the motor must be repaired, or replaced. Before replacing the motor, inspect the case drain hose to be certain that it is not pinched or kinked. A defective hose can cause pressure build up in motor and rupture the seal.

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07 ― Lift Hydraulic Diagnostics

Lift Hydraulic Circuit

Left ElevationCylinder

Right ElevationCylinder

Pressure CompensatedVariable DisplacementPiston Pump

High PressureLift Filter

LiftManifold

SolenoidValveStack

Servo ValveManifold withManual Overrides

To GearboxLube

951753.eps

Cylinder Locking Valves

High PressureLow Pressure

DrainSuction

Static

Ball Valves

The oil flow for the lift (grade) systems, begins at the reservoir where the oil is routed to the inlet of the pressure compensated lift pump. The lift system is a closed center system. This means there is a standby pressure in the system of 2000 psi (138 bar), but no flow, until a system is activated. With all systems deactivated, the pressure in the system increases until a sensing device in the pump senses that the pressure is at 2000 psi (138 bar), this will cause the pump to stop pumping. As soon as the pressure in the system decreases, the pump will begin to stroke again, until the pressure reaches the preset level. Oil flow from the lift pump, with the pump swash plate at maximum angle, is 25 gpm (94.6 lpm) at 1850 rpm. From the pump the oil is routed through the high pressure lift filter to the lift manifold which distributes the oil to the various systems on the machine. A line tapped into the outlet side of the high pressure lift filter supplies lubrication oil to the trimmer gearbox lube system (refer to the trimmer hydraulic system for more information). A line tapped into the lift manifold is

connected to a pressure gauge to monitor the pressure of the system. Oil is routed form the lift manifold to the solenoid manifold and elevatoin solenoid valves under the left side of the operators platform. Oil is also routed from the lift manifold to the solenoid stack valves under the right side of the operators platform.

With the solenoid valve spool in the centered position, the oil flow is stopped. Both grade systems operate the same hydraulically, so the explanation of one is the same for the other.

When the solenoid valve receives an "up" signal from the control loop, the valve spool is shifted. Oil is directed out through one of the work ports of the valve to one of the counterbalance valves. The oil forces the internal check valve off its' seat (in the counterbalance valve) and flows into the piston end of the cylinder. Since the circuit is equipped with double counterbalance valves, the oil flow is stopped, causing pressure to build in the rod end of the cylinder and

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preventing the cylinder from extending. A small port directs this pressure increase to a small shuttle piston in the opposing counterbalance valve, which shifts, lifting the check valve off its' seat. This allows oil from the rod end of the cylinder to return to the opposite solenoid valve port, and out to the reservoir. When the solenoid valve spool returns to neutral, the check valve in each counterbalance valve returns to its' seat, locking the oil in both ends of the cylinder.

When the solenoid valve receives a "down" signal from the control loop, the valve spool is shifted. Oil is directed out through one of the work ports of the valve to one of the counterbalance valves. The oil forces the internal check valve off its' seat (in the counterbalance valve) and flows into the rod end of the cylinder. Since the circuit is equipped with double counterbalance valves, the oil flow is stopped, causing pressure to build in the piston end of the cylinder and preventing the cylinder from retracting. A small port directs this pressure increase to a small shuttle piston in the opposing counterbalance valve, which shifts, lifting the check valve off its' seat. This allows oil from the piston end of the cylinder to return to the opposite solenoid valve port, and out to the reservoir. When the solenoid valve spool returns to neutral, the check valve in each counterbalance valve returns to its' seat, locking the oil in both ends of the cylinder. The elevation cylinders require pressure to extend them and to retract them.

Ball valves are located between the left solenoid valve working ports and the left elevation cylinder. When the ball valves are positioned for trimming operations, individual control of the left and right elevation cylinder by the corresponding solenoid valve is maintained. When both ball valves are rotated 90 degrees for placing operations, control of both cylinders is diverted to the right solenoid valve. This allows the left and right cylinders to float oil between them as needed to maintain contact between the placing hopper wheels and the grade.

Symptom:

All grade systems inoperative, or slow to respond.


Isolate the problem, electrical versus hydraulic. If the system will not respond with the jog switches on the control loops, check the system operation by pressing the override buttons on the solenoid valves. If the system will respond to the override buttons the problem is electrical. Refer to the grade and slope electrical diagnostic section for procedures to follow if the problem is electrical. If the system will not respond

to the override buttons, the problem is in the hydraulic system. Proceed as follows:

1. Lift pressure set too low. Adjust the lift pressure as necessary following the procedures in the Maintenance chapter.

2. Plugged high pressure lift system filter. If the filter indicator light illuminates, depress the test switch and scroll to the filter test screens to determine if the lift filter requires replacement. The filter is of the non-bypass type. If it becomes completely clogged, it will not pass any oil.

3. Defective lift pump. It is possible that the lift pump may have failed, reducing the total flow to the system. If all grade and steering circuits are activated simultaneously, it could cause a pressure drop in the system, resulting in slow response. Check the pump output with a flow meter. A good indication of a defective pump is to compare system pressure with engine rpm. A good pump will hold pressure as engine rpm is decreased. A damaged pump will not hold pressure as engine rpm decreases. The pressure will drop rapidly. Repair or replace the appropriate pump as necessary.


4. Hoses for field installed systems coupled together, or open center valves used. If any systems that draw hydraulic oil from the lift system have been added to the machine, make certain that when the system is removed the hoses are not connected together. If the hoses are connected together, it will create a direct path to tank for the oil. Also, any system that may be field installed, must utilize a closed center valve (valve that blocks oil flow in neutral).

Symptom:

One grade system inoperative, or slow to respond.


Isolate the problem, electrical versus hydraulic. If the system will not respond with the jog switches on the control loops, check the system operation by pressing the override buttons on the solenoid valves. If the system will respond to the override buttons the problem is electrical. Refer to the grade and slope

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electrical diagnostics section for procedures to follow if the problem is electrical. If the system will not respond to the override buttons, the problem is in the hydraulic system. Proceed as follows:W55

WARNING!! !Injection or Flying Object Hazard! Remove all weight from cylinder before removing locking cartridge. If cartridge is removed with weight on the cylinder, cartridge and high pressure hydraulic oil will be expelled rapidly and machine will drop. Failure to comply could result in serious injury or death.951852

1. Faulty locking valve. If the machine will raise, but not lower, or lower, but not raise, suspect that the shuttle piston in the locking valve is defective. Lower or raise the machine to remove all weight from the cylinder and stop the engine. Swap the suspected valve with the valve for the opposite side of the machine. If the fault moves to the opposite system, replace the locking valve.

2. Excessive leakage past spool in the solenoid valve or past the packing in the cylinder. Swap the solenoid valve with one from the opposite side of the machine. If the problem transfers to the opposite side, replace the solenoid valve. If the problem remains in the same system, suspect the cylinder. A cylinder can be checked for internal leakage by disconnecting the line on the lower end (rod end) of the cylinder with the cylinder fully extended. Apply pressure to the upper end. If fluid flows from the open fitting on the lower end, the internal packing is damaged and must be replaced.

Symptom:

Improper or slow grade control. One side cannot be raised or lowered by itself. Must raise or lower both sides simultaneously.


This is a good indication that the hoses may be crossed on the solenoid manifold.

Machines equipped with ball valves will react in a slow manner on one side versus the other. If one valve is turned correctly but the other is not, very slow control will be evident on one side versus the other. Make certain both valves are rotated in the same flow direction for correct operation in either the trimming or placing modes.

Note: Because hydraulic oil floats between the left and right elevation cylinders during placing operations, one side may raise or lower before the other. This is normal due to a difference in weight on one side versus the other.

Symptom:

Gradual swales in grade.

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1. A sticky solenoid valve can cause this type of symptom. Sticky valve spools are caused by contaminated oil. Sticky valve spools can sometimes be freed by pressing the manual override buttons on the solenoid valve. This throws the valve spool from one extreme to the other and the particles causing the spool to stick tend to wash out. A sticky spool can be detected on the control loop display meter by two methods:

If the deviation indicator overshoots when it approaches center from an offset.

If the deviation indicator tends to hang to one side of center and won't re-center. This will tend to happen when approaching center from either side. It shows that a small amount of electrical signal to the valve doesn't have enough physical power to overcome the resistance of the sticky spool.

950040

2. Bolster lockout blocks in place. Remove the lockout blocks from the bolster to allow the machine frame to tilt as necessary.

3. Other causes may be loose stringline, incorrect tension on the sensor hub spring or the sensitivity is set too low. Refer to the proper chapter for adjustment procedures.

951056

4. Elevation cylinder pivot joints seized. Remove all weight from the elevation cylinders. Remove the cylinders and make certain the pivot joints at either end of the cylinders are free to rotate. This may also cause severe scarring of the cylinder housing and damage to the internal piston packing. Lubricate and repair or replace any damaged parts.

Symptom:

Grade cylinder will not hold in the extended position overnight.


WARNING!! !Injection or Flying Object Hazard! Remove all weight from cylinder before removing locking cartridge. If cartridge is removed with weight on the cylinder, cartridge and high pressure hydraulic oil will be expelled rapidly and machine will drop. Failure to comply could result in serious injury or death.

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951852

1. Locking valve not holding the cylinder extended. Lower the machine as far as possible to remove all weight from the cylinder and stop the engine. Remove the locking valve cartridge from the affected system and swap it with the cartridge from the unaffected system. If the problem transfers to the previously unaffected side, the locking valve is defective. Remove the valve, clean and inspect it and reinstall it. If it still does not operate properly, replace the valve.

2. Internal cylinder packing leaking. If the problem remains on the same leg after swapping the locking valve cartridges, remove and repair the cylinder packing in the cylinder.

Symptom:

Front of one track will not stay on the ground when the conveyor is swung to the opposite side during placing operations.


1. Hoses from left elevation cylinder not connected to tees for right solenoid valve. Rotate the ball valves as instructed in the Placer Setup chapter.

2. Bolster lockouts not in place, allowing machine to rock over when the rear conveyor is loaded with concrete and the receiving hopper is empty. Install bolster lockouts as instructed in the Placer Setup chapter.

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08—Hydraulic Reservoir drawing

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09—Rear Conveyor Hydraulic Drive Drawing

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10—Trimmer/Auger Drive Hydraulic Drawing

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11—Track Drive Hydraulic Drawing

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12—Lift Pump Hydraulic Drawing

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13—Machine Lift Hydraulic Drawing

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14—Hitch/Lift Arms & Vibrator Hydraulic Drawing

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6-36

15—Conveyor Lift Hydraulic Drawing

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16—Conveyor Swing Hydraulic Drawing

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17—Conveyor Fold Hydraulic Drawing

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18—Case Drain/Lube Hydraulic Drawing

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19—Oil Cooler Hydraulic Drawing

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20—Main Filter Hydraulic Drawing

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6-43

21―Trimmer remote connections

6-44

22―Machine and Accessory CAN cables

6-45

23―Cable Assemblies

6-46

24―Left Slave Assembly

6-47

25―Right Slave Assembly

6-48

26―Console Panel Assembly

6-49

27―Master Controller Assembly

6-50

28―Operator Remote Assembly

6-51

29―G+ Control Panel Assembly

6-52

30―Accumulator Wiring Assembly

6-53

31―Hopper Remote Wiring Assembly

6-54

32―Sensor Bulkhead Assembly

6-55

33―Cat C11 Miscellaneous Wiring Assembly

6-56

34―Engine Control Panel Assembly Tier IV

6-57

35―Miscellaneous Wiring CAT Tier IV

6-58

Documents

Chapter VI Diagnostics 6-1