BRAKE TIPS

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					                                                                               BACKGROUND


                                       BRAKE TIPS

TIP #1: AUTOMATIC SLACK                                  TIP #4: PLAN AHEAD
ADJUSTERS
                                                         Replace the complete hardware when
Just because it says it's automatic, doesn't             servicing your cam brakes.
mean it's maintenance-free.
                                                         Planning ahead could avoid unnecessary
For Automatic Slack Adjusters (ASAs) to                  downtime for your vehicle. When you
do their job, you must do yours. That                    service your cam brakes, take time to
means checking to ensure that the slacks                 replace all the springs, anchor pins,
were installed properly. Also, make sure                 bushings and rollers, not just the shoe
the ASAs are lubricated. Check the brake                 return springs. Spending a little extra
system for any damage, since ASAs are                    money up front can save you valuable
not a cure-all for deficiencies in the                   time and money later. When it's time for
foundation brake.                                        that additional performance during
                                                         stopping, the extra cost will seem
TIP #2: CAM BRAKES                                       inconsequential.
Be sure to replace the cam brake return
springs at every reline.                                 TIP #5: BRAKE DRUMS

Not everyone believes it is necessary to                 Just because they fit doesn't mean they'll
replace cam brake return springs each                    perform the same.
time cam brakes are relined. But, wouldn't               Never judge a drum solely by its fit. In the
you rather do it then, instead of out on the             brake drum market, there are two basic
road? Besides convenience, the return                    types of drums — cast and composite, like
spring is critical to the alignment, the                 the Meritor® SteelLite™ X30. They differ in
accurate return of the brake away from                   their abilities to absorb and dissipate heat.
the drum and brake adjustment with the                   A drum's ability to provide satisfactory
automatic slack adjuster.                                performance depends on its ability to
                                                         dissipate heat. Using different weight or
TIP #3: CAM BRAKE LININGS                                types of drums on the same axle could
The brake lining block must be OEM                       result in unbalanced braking and improper
quality.                                                 functioning of the automatic slack
                                                         adjuster. Poor brake performance due to
Your vehicle’s brake system requires the                 uneven lining and drum wear will occur.
correct lining material to perform a specific
job. Change the type of lining material and              TIP #6: THE PRESSURE'S ON
the job doesn't get done properly.
Insisting on the same brand of friction                  Make sure cam brake air chambers are of
material as the OEM-quality assures you                  same size and type.
fewer replacements and greater                           When changing cam brake air chambers,
compatibility with your present system.                  make certain that all brake chambers on
                                                         the same axle are the same size and type.
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In doing so, you will ensure proper brake                   poor brake performance or decreased
balance. An unbalanced brake system                         lining life.
would result in unacceptable lining and
drum                                                        TIP #10: ANTI-LOCK BRAKING
                                                            SYSTEMS
TIP #7: BRAKE REPLACEMENT                                   Anti-lock braking systems are not a "cure
PARTS                                                       all" for brake maintenance.
There are no unimportant brake                              ABS effectively reduces wheel lock-up
replacement parts.                                          that can result in spin-out and loss of
Meritor® brakes work as a system. When                      steering control, which in turn helps to
an original part is replaced by a "will-fit"                minimize accidents, repairs and insurance
part, performance of the entire system                      costs. To achieve these benefits of ABS,
may be compromised. A will-fitter's parts                   make sure your foundation brakes are
may be less expensive to buy initially, but                 kept in adjustment and that you follow
they could cost you more down the road in                   preventive maintenance guidelines to
downtime or reduced performance. So,                        properly maintain your braking system.
don't take a chance with something as
important as your brakes. Replace brake                     TIP #11: CAM HEADS
parts with OEM quality standard parts.
                                                            They may look the same, but they don't
                                                            provide the same performance.
TIP #8: TRAILER CAM BRAKES
                                                            Two cam head profiles may appear to be
Long-life bushings require proper                           identical when viewed with the naked eye,
lubrication for maximum performance.                        but very small differences can be
Yes, it's true. ArvinMeritor has made                       significant to the performance of your
obsolete the frequent replacement of                        brakes. Each brake manufacturer designs
spider cam bushings on your trailer axles.                  its cams somewhat differently. Some are
But, it's also true that to get the longest life            engineered to provide constant lift while
out of these bushings, proper lubrication is                others promise constant torque.
necessary. We recommend greasing them
                                                            Conclusion? As with all brake components,
at least four times during the life of your
                                                            use the proper replacement cam. Failure to
brake lining.
                                                            use the proper cam can result in an
                                                            unbalanced brake system and
TIP #9: LONG LIFE BRAKE KITS
                                                            unacceptable lining and drum life.
Not all aftermarket kits are created equal.
Brake shoes, rollers, camshafts and shoe                    TIP #12: AUTOMATIC SLACK
return springs for long life brakes are                     ADJUSTERS
specifically designed as a system for                       Never mix your automatic slack adjusters
optimum brake performance. These                            on the same axle.
components depend on each other to
                                                            When it comes to replacing your
provide brake performance truck
                                                            automatic slack adjusters, always be sure
operators can depend on. Using non-OEM
                                                            to replace them with what was originally
spec level components for maintenance or
                                                            designed for the braking system. In other
to upgrade from standard to long life
                                                            words, never mix two different brands of
brakes could result in unbalanced braking,


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automatic slack adjusters on the same                   life, maintenance problems and drum
axle. This would result in uneven brake                 cracking on your drive or trailer axles.
wear, unbalanced braking and poor brake
performance.                                            TIP #16: BRAKING TECHNIQUE
                                                        On a mountain descent, always snub,
TIP #13: IMPROVE BRAKE
                                                        never drag your brakes.
PERFORMANCE
                                                        When coming down a mountain with a
Always make sure cam rollers are                        fully loaded vehicle, it’s always best to use
correctly lubricated.                                   short 20 to 30 psi brake snubs in your
The proper way to lubricate a cam roller is             descent.
directly in the web roller pocket and not at
the cam to roller contact area. If you do               Why? Because if you drag your brakes
this correctly you will avoid creating flat             and your air system is not properly
spots. These flat spots adversely affect                balanced, certain brakes will end up doing
the brake adjustment which may result in                more of the work than others. This will
premature brake wear or reduced braking                 lead to excessive temperatures and brake
performance. The best time to change                    fade resulting in increased stopping
your cam rollers is when you reline. That               distance and shorter lining life.
will save you both time and money.
                                                        TIP #17: HAND VALVES
TIP #14: GIVE YOUR BRAKE A BREAK                        Always give your hand valve a break.
Make sure your air brake valve crack                    Because trailer brakes are designed to
pressures stay the same.                                work in conjunction with tractor brakes, it’s
When you replace the valves in your air                 recommended that you not use the hand
brake system, make sure that the new                    valve for braking, especially on long
valves have the same crack pressure as                  descents.
those that are being replaced.
                                                        If you overuse your hand valve, the trailer
Why? Because replacing a valve with one                 brakes do more than their fair share of the
that has a higher or lower crack pressure               braking. This can result in excessive brake
than the original valve can result in an                temperatures and shorter lining life on the
unbalanced brake system and                             trailer brakes.
unacceptable lining and drum life.
                                                        TIP #18: BOBTAIL PROPORTIONING
TIP #15: REPLACING BRAKE LININGS                        VALVES ON OLDER MODEL VEHICLES
When it comes to replacing single or                    Bobtail proportioning valves cut rear
tandem axle brake linings, the best advice              wheel lockup and improve controlled
is…replace one, replace them all.                       stops.
Always replace the linings on both brakes               If an older model tractor is running in a
of a single axle, or on all four brakes of a            bobtail mode, the presence of a bobtail
tandem axle at the same time. If you                    proportioning valve automatically adjusts
don't, you could experience brake balance               braking pressure for increased stability
problems. Plus, not replacing a unit's                  and control. Your tractor’s rear axle
brake linings at the same time may                      braking pressures are reduced by as
contribute to uneven wear, reduced lining               much as 70%, minimizing the potential for

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rear wheel lockup. This allows your front   conditions. Or, Roll Stability Control (RSC)
axle brakes to do their share of work and   for tractors and Roll Stability Support
stop straight.                              (RSS) for trailers – both of which help
                                            maintain vehicle stability and aid in
However, because the valve reduces rear     reducing vehicle rollovers.
brake pressure, drivers must compensate
by increasing the pedal force to stop the   TIP #20: TRAILER ABS WARNING
vehicle.                                    LAMPS
                                            Be alert to what your trailer ABS warning
TIP #19: SPEC’ING ABS OPTIONS
                                            lamp is telling you.
Careful thought is a must when choosing     If the trailer ABS warning lamp comes on
the right ABS options.                      and stays on once the vehicle is moving,
When spec’ing the optimum ABS, it is        or if it comes on and stays on during
important to ask a supplier what options    braking, there may be an ABS
are available with their system.            malfunction. While the vehicle can be
                                            operated to complete the trip, it is
Today, there are a variety of ABS options   important to have your vehicle serviced as
that can provide drivers with added peace   soon as possible to ensure proper braking
of mind, as well as provide an additional   performance. As with any safety system, it
measure of assurance for your operation.    is important not to ignore this warning.
Options such as Automatic Traction
Control (ATC), which provides added                            ###
traction on slippery or adverse road




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