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SERVICING CLUTCHES
Chapter 3 Page 49 Lab manual
Page 45 Classroom Manual
OBJECTIVES
Diagnose clutch-related problems. Inspect, adjust, replace clutch linkage. Inspect, adjust, repair, and replace clutch
slave and master cylinders, & lines. Inspect, adjust, and replace release
bearing lever, and pivot. Inspect and replace pressure plate.
Page 49
OBJECTIVES
Inspect and replace clutch disc assembly. Inspect and replace pilot bearing. Inspect or replace flywheel ring gear. Inspect block, bellhousing, case surfaces. Measure flywheel runout, and crank endplay. Measure clutch housing-to-block runout. Inspect, replace, align power train mounts.
Page 49
CLUTCH PROBLEM DIAGNOSIS
The more information you have, the easier it is to properly diagnose it.
Talk to the customer, ask questions. Road test the vehicle with the customer
driving, if possible. Look for driving habits that cause failure. Listen carefully to changes in the noise.
Page 49
TROUBLESHOOTING GUIDE
Noises Binding Slippage Pulsation Chatter
Page 51 to 54
CLUTCH SLIPPAGE
Engine speed increases vehicle speed does not.
Slipping is caused by:» Improper adjustment (too tight)» Worn disc» Contamination of the disc (oil)
Adjustment clearance decreases with disc wear.
Page 54
CLUTCH CHATTER
Clutch chatter is a shaking or shuddering. Clutch chatter is cause by:
» Broken motor mounts» Glazed clutch disc» Worn U-joints» Worn pilot bushing
See page 55
OTHER CLUTCH NOISES
Most clutch noises are caused by bearings and bushings.
Bushings squeal or howl. Bearings grumble or grate. Misalignment is a common cause of
clutch problems.
Page 56
CLUTCH VIBRATES
Clutch vibration can occur at any clutch position.
Can “feel” the vibration, and sometimes hear it also.
Page 57
DRAGGING CLUTCH
Dragging results from the clutch not completely disengaging.
Maximum spin down time 5 seconds. Dragging is caused by:
» Warped disc or Pressure plate» Loose disc facing» Incorrect clutch pedal adjustment.
Page 57
PULSATING CLUTCH PEDAL
Pedal pulsation s a rapid up-and-down movement of the clutch pedal as the clutch engages or disengages.
Pulsating is caused by:» Broken, bent, or warped release levers.» Misaligned bell housing.» Warped pressure plate, disc, or flywheel.
Page 57
BINDING CLUTCH
Clutch pedal does not operate smoothly. Possible causes of binding are:
» Worn front bearing retainer.» Dirty or worn input shaft splines.» Bent or worn linkage.
Page 57
MECHANICAL CLUTCH CONTROLS
Worn bushings, bent rods, broken springs, and damaged cotter pins can cause excessive pedal effort when operating the clutch.
Free-play decreases as the clutch disc wears.
Worn linkage makes free-play adjustments inaccurate.
Page 58
CHAPTER 3
pg 56 C
CABLE
FREE-PLAY ADJUSTMENT
Free play is the clearance between the clutch release fingers and the release bearing.
Free-play is measured at the pedal. Free-play is critical to clutch life. Insure return springs are in place.
Page 59
SELF ADJUSTING
Pg 57 C+
HYDRAULIC CLUTCH CONTROLS
Hydraulic clutch components are serviced like hydraulic brake components.
Common hydraulic problems are:» Fluid leaks» Worn-out piston seals» Air in the system» Corrosion buildup
Page 63
HYDRAULIC
Pg 58 C
SLAVE CYLINDER
Pg 59 C
ADJUSTABLE SLAVE CYL.
Pg 59 C
CLUTCH DISC
Clutch disc transfers power from the flywheel to the transmission input shaft.
Disc must remain free of oil. Clean hands. Most clutch discs contain Asbestos. If clutch disc is removed, replace if more
than 50,000 miles.
Page 74
FLYWHEEL
Scored flywheels can be resurfaced. Check flywheel runout. Check crankshaft endplay. Clean oil and abrasives from flywheel. Check ring gear teeth. Mark flywheel and crankshaft for reassemble.
Page 76
REMOVING THE CLUTCH
Caution Mark driveshaft before removal. Caution Asbestos Warning check bolt length. Match new parts with old parts
Page 79 - 82
PILOT BUSHINGS
Three Types» Bushings» Ball Bearings» Torrington Needle Bearings
Use a tap to remove Bushings. Use a puller to remove bearings.
Page 82
RELEASE BEARING
Three Types» Non Constant Running Release Bearing
– Adjustable Mechanical Linkage– Adjustable Hydraulic– Adjustable Cable
» Constant Running Release Bearing– Self Adjusting Cable – Non Adjustable Hydraulic System
» Internal Hydraulic Release Bearing (Pg 86)
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