Embed Size (px)
DESCRIPTION
The exclusive maintenance resource for the transit and motorcoach industry.
Citation preview
JULY
.201
5
BUSRIDEMAINTENANCE.COM
THE EXCLUSIVE MAINTENANCE RESOURCE FOR THE TRANSIT AND MOTORCOACH INDUSTRY
Monitor tire wear p6 | ABA launches BusMARC p7
p4WHAT OPERATORS NEED TO KNOWAIR-DISC BRAKES:
2 BUSRIDE MAINTENANCE | JULY.2015 busridemaintenance.com
CEO Judi Victor
Publisher Steve Kane
Associate Publisher David Hubbard
Editor in ChiefRichard Tackett
Art DirectorStephen Gamble
Account ExecutiveJeanette Long
Accountant Fred Valdez
VOL. 05 • NO.7
A publication of:
BUS INDUSTRY SAFETY COUNCIL
FROM THE EDITOR IN CHIEF
DepartmentsFrom the Editor in ChiefProducts and Services
2
3
JU
LY 2
015
CO
NTE
NTS Air-disc brakes: What
operators need to knowWhat do bus and coach operators need to know about bus brake systems, brake technology, and replacement components and parts?
Where does the rubber from tire wear go? By Christopher W. Ferrone
ABA announces BusMARC New council will raise the level of maintenance awareness in the intercity bus and motorcoach industry
4
6
7
On the cover:
Air-disc brakes – what operators need to know
In this issue, BUSRide Maintenance takes a close look at air-disc brakes — and provides an in-depth Q&A about bus brake systems,
purchasing advice, safety standards and replacement components/parts.Brake OEMs (Bendix Commercial Vehicle Systems, DuraBrake, ProTec
Friction Group and Meritor WABCO) talk about the advent of air-disc brakes, best buying practices, regulations, standards and specifications.
In addition, these industry leaders share their recommendations regarding the advantages of like-for-like purchases, as well as the advantages of air-disc brakes over brake drums. They talk openly about the pitfalls to avoid in the brake system aftermarket and they provide critical advice about vetting aftermarket suppliers.
We must never forget that motorcoaches and transit buses carry precious cargo. For this reason, there is perhaps no more essential bus component than an effective braking system. Expand your knowledge of aftermarket brake purchasing. This is not a place to cut corners.
Richard TackettEditor in ChiefBUSRide Maintenance Magazine
POSTMASTER: Please send address changes to:
BUSRide Maintenance Magazine4742 North 24th Street, STE 340Phoenix, Arizona 85016Phone: (602) 265-7600 Fax: (602) 277-7588 busridemaintenance.com
busridemaintenance.com | BUSRIDE MAINTENANCE 3
PRODUCTS & SERVICES
OPTI-PRO finds leaksThe Tracerline® TP-8655 OPTI-PRO™ Plus is a cordless,
rechargeable, true UV (violet light) LED leak detection flashlight. It emits less visible light, making leaks clearer and easier to spot. The OPTI-PRO Plus is engineered with a high-output violet light LED that provides optimal fluorescent dye response and contrast. The OPTI-PRO Plus has an inspection range of 20 feet (6.1 m) or more. Its lightweight and compact body can easily get into tight, cramped areas that larger lamps can’t. The flashlight’s rugged, corrosion-resistant, anodized aluminum body stands up to years of heavy shop use. With power comparable to high-intensity 125-watt lamps, it provides four hours of continuous inspection between charges.
Tracerline®
Westbury, NY
Trans/Air improves reliabilityTrans/Air’s TM43 is a heavy-duty transit compressor for
buses and coaches. It provides the high reliability and capacity only available from a transit compressor design for heavy-duty split system and rooftop applications. With a capacity of 80K (SAE) / 128K (IMACA) Btu/hr, features include a 10-cylinder swash plate for smooth operation, heavy-duty transit clutch in multiple configurations, flexible port and mounting design for easy installation, high and low pressure switches for protection, oil sump for reliability, and compact / light-weight design enabling mounting directly to the engine. Mount and drive kits are engineered for Ford F650/F750, Freightliner M2, and selected conventional school bus chassis.
Trans/Air ManufacturingDallastown, PA
Warm up with Thermo ProThe Thermo Pro 90 engine-off coolant heater with up to
31,000 Btu/h of heating power offers new features specially designed for specialty commercial vehicles. It features improved fan motor durability and is bio-diesel compatible.
The Thermo Pro 90 offers offer quick warm-up times, low power consumption and high product quality. The Thermo Pro 50 is capable of up to 17,000 Btu/h of heating power and is available as a standard or heavy-duty kit. Both are available immediately, as compact kits (12V) or with enclosure box (12V and 24V).
Webasto Thermo & Comfort North AmericaFenton, MI
Voith debuts eco-friendly drive systems
With DIWA.6, Voith offers the ideal automatic transmission to meet the rising demand for clean and fuel-efficient vehicles for modern public transport, especially in view of the Euro 6 requirements. Specifically developed for city buses, the DIWA transmission offers the best preconditions for economical operation. Compared to its predecessor model, it saves almost another five percent of fuel. This is made possible by the topography-dependent gear-shifting program SensoTop, as well as the need-based reduction of the operating pressure and an intelligent start-up management that avoids starting against the active service brake.
VoithHeidenheim an der Brenz, Germany
4 BUSRIDE MAINTENANCE | JULY.2015 busridemaintenance.com
The attempts to pressure balance, wear balance and heat balance the brakes come baked into the OEM design. Purchasing like-for-like when a replacement is necessary is important to maintaining
those specifications. (Photograph courtesy of DuraBrake, Inc.)
WHAT OPERATORS NEED TO KNOWAIR-DISC BRAKES:
What do bus and coach operators need to know about
bus brake systems, brake technology, and replacement
components and parts?
In terms of foundation brakes, transit buses top the list of the most difficult applications to supply and manage (ahead of refuse trash collection).The reason is the harsh operational environment in which
the buses typically travel fully loaded on most mornings and evenings in cities with dense populations. Because transit buses make so many stops throughout the day, thermal energy is always a critical consideration. Energy builds in the brake system much faster than it releases into the air, and the brakes just get hotter and hotter.
Whereas brake drums were once the norm on buses, over the last 10 years motorcoaches have transitioned to all-wheel disc brakes. More recently, they’ve elevated as an option for transit buses.
The benefits of air-disc brakes over drum brakes include lighter-weight components, improved stopping distance and faster maintenance.
busridemaintenance.com | BUSRIDE MAINTENANCE 5
The brake rotor on air-disc brakes gets good thermal management because the hottest surface faces outward to the air and escapes in the wind. This alone reduces the major thermal energy that is so damaging. The hotter the brakes, the faster the pads and rotors wear.
What are the dangers of shopping solely on price?
Clearly the associated costs of vehicles equipped with disc brakes are higher, as well as for replacement parts. For safety-minded operators, this should not come into play. Replacement brake parts are safety-related components. Replacing a part is not just about replacing it with a close facsimile. It is about taking steps to ensure the highest quality, especially considering the safety of the passengers. They deserve nothing less.
Bus and coach operators need to be cognizant of the proliferation of counterfeit brake products made to look incredulously similar to OEM products. In some cases, it is often difficult to distinguish the fake from the original. It might even carry the OEM logo, brand name or part number. Unless operators really know the company, a price that seems too good to be true probably is.
One suggested best practice for operators purchasing brakes parts is to vet aftermarket suppliers before they make any purchases. The more reputable suppliers of brakes have usually been in business for years, while others may turn out to be little more than a flash in the pan. There are aftermarket suppliers that import from overseas without ever taking time to learn the specifications and requirements for the safest brake parts.
The cheapest brake job may compromise safety. On the same hand, the most expensive parts may not prove any safer than the standard part. Customers should research aftermarket suppliers, relying on test data, customer references and knowledgeable safety-related information.
What overriding regulations, minimum standards and specifications dictate brake performance in heavy-duty buses and motorcoaches?
Federal Motor Vehicle Safety Standards (FMVSS) 121 establishes the minimum safety standards required for buses and motorcoaches with air brake systems over 10,000 GVWR to comply with the maximum stopping distance of a vehicle according to the National Highway Transportation Safety Administration (NHTSA). FMVSS 121 states buses must be equipped with an antilock brake system (ABS) and be able to stop under a certain distance when moving at a maximum speed — typically evaluated using a dynamometer in a laboratory setting.
Though the government sets the performance standards for brake systems of new vehicles, it does not establish such specifications for replacement parts.
Given that a large percentage of consumer complaints to NHTSA involves brakes, the brake system is clearly one of the most critical elements of vehicle safety.
Different friction materials used today often have their separate design compromises.
While one may offer superior heat for better braking performance, it
may also be noisier or prone to depositing unsightly brake dust on the wheel rims. Another friction compound may have a soft feel and work quietly, but wear out much
more quickly.Technicians must inspect regularly
to ensure the minimum thickness of the brake rotors do not fall below
specifications. For example, whereas the original brake thickness of the surface the pads press against may start at 45mm, the OEM rotors should always specify the minimum thickness before the rotor is no
longer safe. Technicians should always replace any rotor that falls the minimum thickness. During an official safety inspection, an operator may receive a citation for driving a vehicle with a minimum thickness lower than the written specification.
Describe some of the newest developments in brake technology.
Prior to antilock braking (ABS), required since 1998, brakes were entirely a mechanical function. ABS introduced electronics into the brake equation and became a great platform for additional technologies such as ESC and collision mitigation systems.
Some manufacturers have increased the content of expensive alloys in their brake rotor such as molybdenum, nickel and chromium in order to increase the strength and life of these parts. Alloy additives increase cost but they offer performance with longer life benefits. Unfortunately, cost savings often drive companies to overlook the benefits of a quality product.
Carbon and ceramic composite brake-rotor developments are still on the drawing board, but the benefits would be a weight reduction by 40 to 50 percent. This is theoretically a longer life and they may never need replacing. Again, the cost would be significantly higher than conventional metal parts.
Can you offer specific guidelines and recommendations to help bus and coach operators make safer, more cost-efficient choices in the area of aftermarket brake repair and maintenance?
Strive for a like-for-like replacement. Wear and performance always suffers with replacement parts of different characteristics. Typically, one axel does less while another works harder more to compensate.
Ideally, an operator does not want to use any replacement part that interferes with the original system design. The attempts to pressure balance, wear balance and heat balance the brakes come baked into the OEM design. Purchasing like-for-like when a replacement is necessary is important to maintaining those specifications.
The companies DuraBrake, Meritor WABCO, ProTec Friction Group and Bendix Commercial Vehicle Systems contributed to the discussion on brakes for commercial vehicles.
The benefits of air-disc brakes over drum brakes include lighter-weight components, improved
stopping distance and faster maintenance. (Photograph courtesy of DuraBrake, Inc.)
6 BUSRIDE MAINTENANCE | JULY.2015 busridemaintenance.com
A number of factors affect the condition of a tire.
Where does the rubber from tire wear go?By Christopher W. Ferrone
A great episode from Seinfeld has Jerry musing about where the rubber on his BMW tires goes when it rubs off.
This is truly an enigma. Like Jerry, it’s good to stop and remind ourselves of all that goes on with a set of tires. As tires wear, the material does in fact deposit onto the roadway and goes undetected because it happens so gradually.
The mechanical function of the tire casing is to contain the air pressure that supports the vehicle load, assure the function of the suspension by absorbing road irregularities, resist lateral drifting and centrifugal force, and transmit the torque necessary to move and stop the vehicle.
A number of factors affect the condition of a tire: the nature of its application for line haul, stop-and-go traffic (or a mix of both), the number of axles on the vehicle, overall maintenance of the tire during its life cycle and inflation pressure.
The major suspension and alignment adjustments control tire wear and condition. Technicians must monitor toe-in and toe-out, caster angle and camber angle. However, not all vehicles have a front axle that allows the control of these adjustments. Therefore, it is of vital importance to know the type of front axle on all vehicles and the allowable adjustments.
The most controlling factor in tire wear may be its inflation pressure. For every 10 psi a tire is under inflated, the life cycle of the tire is reduced by 10 percent. The amount of air in the tires affects the weight distribution between the wheels. An under-inflated tire does not carry its share of the load. This condition affects torque, traction, steering, alignment, braking and cornering, and may cause pulling from side to side.
A tread separation usually means the tread has separated from the casing, disconnecting from the outermost steel belt. The outermost steel belt has become detached from the lower steel belt and the rest of the casing. Tread separation can be the entire tread or simply a section of the tread. This usually occurs later in the life of the tire casings unless a traumatic event has occurred.
A hole or some sort of damage that starts in the sidewall is normally the cause of a sidewall failure. Curbing the tire, striking a sharp object, age cracking and other structural issues all contribute to sidewall failures.
It is my belief that operators should never use retread or recapped tires on a motorcoach for any reason. When they experience failure they can damage the vehicle with the delaminated tread that is rotating with the tire casing, just as a circular saw would cut air hoses and suspension bellows during this type of failure.
Typically, the life cycle for a tire is four to six years, which corresponds to the average useful life of a tire casing. Despite the condition of the tread, tires should be taken out of service when they reach the four to six year mark. The DOT number embossed on the side of the casing notes the age of the tire. The last three numbers indicate the week and year of manufacture.
Technical staff must understand what affects tire condition and respond proactively. They must routinely monitor wheel alignment, inflation pressure and suspension adjustments in order to maintain proper tire performance. Additionally, if the vehicle has a steerable tag axle, technicians must also monitor those components to ensure the expected life cycle for the tag axle tires.
busridemaintenance.com | BUSRIDE MAINTENANCE 7
Phot
o co
urte
sy o
f ABC
Com
pani
es.
ABA announces BusMARCNew council will raise the level of maintenance awareness in the intercity bus and motorcoach industry
The American Bus Association is again taking a significant leadership role in the motorcoach industry, announcing the formation of its new Bus Maintenance and Repair Council (recognized as BusMARC).
According to ABA, the BusMARC mission is to:• Raise the level of maintenance awareness in the intercity bus
and motorcoach industry • Provide shop managers with the tools to build and improve
their existing programs• Provide relevant and timely information to assist maintenance
personnel with inspections and audits • Share information, including industry best practices• Bring together experts to collaborate on these
maintenance issues“We have created BusMARC because ABA and its members
believe there is a significant need in the motorcoach industry to assist companies of all sizes when it comes to collaborating on maintenance and repair issues,” says ABA President and CEO Peter A. Pantuso. “Industry and government officials understand that well-maintained motorcoaches, on regular maintenance cycles, are the safest vehicles on the road.”
ABA believes BusMARC will enhance safety for the hundreds of millions of people who travel by bus each year. It sees BusMARC as improving the relationship between motorcoach owner/operators, company maintenance directors, operations staff, coach OEMs, vendors and suppliers.
ABA has named Mike McDonal, manager of the Maryland-based motorcoach company Eyre Bus Tour and Travel, as chairman. McDonal is a past chairman of the Bus Industry Safety Council (BISC) and currently serves on a number of key industry-related committees.
Membership in ABA is not a requirement for BusMARC membership. ABA invites all motorcoach owners, operators, maintenance professionals, shop supervisors and leaders from other segments of the industry to join. The first meeting of BusMARC will be held in conjunction with the ABA’s Marketplace, January 9-12, 2016, in Louisville, KY.
“Recently the ABAs leadership including Board Chairman John Meier, Vice Chairman Don DiVivo and board members, began discussing the need and concept for BusMARC,” McDonal says. “We agree that developing BusMARC is the next step because of the critical role maintenance is now playing in government compliance and the overall wellbeing of our travelers.”
He says by sharing the collective expertise of maintenance professionals, BusMARC can raise the standards and improve relationships with the OEMs.
“It’s our goal to make sure the buses are on the road every day,” McDonal says. “The equipment must be maintained as well as possible to protect lives and reduce downtime.”
ABA Chairman John Meier says Mike McDonal has everyone’s full support, and sees BusMARC helping the association tremendously to take a significant leadership role in the industry that benefits members and the traveling public.
BUSRide Magazine wants to hear
from you!
Tell us what you think the single most important motorcoach industry event has been in the past 50 years –
and you could win a
Simply email [email protected] and we’ll follow up with you by email or by phone. You’ve got 50 words (one for each year of our anniversary) to tell us
what rocked the motorcoach and transit industries most in the past five decades.
$100 AMAZON GIFT CARD!
