ANTI-LOCK BRAKING SYSTEM (ABS)
PART 8: MAINTENANCE AND SERVICE
– 214 –
Y53-6032
(R05/10)
Below are some general notes on repairing your anti-lock
braking system:
• The foundation brake system must be in proper work-
ing order to ensure the best ABS performance.
• Before welding anywhere on the vehicle, detach the
ABS ECU connector and all other electronic control
units.
• Never detach the ECU connector with the ignition
turned on.
• Do not attempt to repair ABS/ASR/ATC electrical
cables that are outside the vehicle. Replace faulty
cables as an assembly.
• When servicing brakes, hubs, or axle, recoat the ABS
sensors with anti-seize compound. Make sure the
sensor is pushed against the pulse wheel after the
hub is reinstalled. On rear axles, the sensor should be
pushed fully into the mounting block before reinstall-
ing the hub.
• Check ABS wiring harnesses and piping periodically
for chafing or other problems. No regular mainte-
nance is required on the ABS components.
• During wheel balancing, dyno testing, or any time the
ignition is on with part of the ABS disconnected, a fail-
ure code will be recorded. After servicing or testing of
the vehicle is completed, clear the failure codes.
If, due to operating conditions, a brake application causes
either wheel on the same axle to begin skidding, wheel
speed sensors immediately signal the anti-lock controller
in the modulator assembly. The controller responds
instantly by signaling the solenoids in the modulator which
activate the air valves, reducing application pressure as
needed to prevent the wheels from locking up. If this over-
riding correction is effective, application pressure is
allowed to build up to the original input.
Any malfunction of the anti-lock system on one or more
axles will cause the system to fail-safe, and the panel-
mounted amber warning light will come on, indicating both
a malfunction, and automatic shut-down of the system. If
the air system is intact (indicated by the pressure
gauges), the service brakes will continue to function nor-
mally, but without benefit of the anti-lock feature.
Y53-6032.book Page 214 Monday, May 24, 2010 3:37 PM
Summary of Contents for Peterbilt 587
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