Bendix Commercial Vehicle Systems ATR-1 ANTILOCK TRACTION RELAY 02/11 - Manual (Page 7)

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7. Never connect or disconnect a hose or line
containing pressure; it may whip. Never remove
a component or plug unless you are certain all
system pressure has been depleted.
8. Use only genuine Bendix ® brand replacement parts,
components and kits. Replacement hardware,
tubing, hose, fi ttings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifi cally for such applications and
systems.
9. Components with stripped threads or damaged
parts should be replaced rather than repaired. Do
not attempt repairs requiring machining or welding
unless specifi cally stated and approved by the
vehicle and component manufacturer.
10. Prior to returning the vehicle to service, make
certain all components and systems are restored
to their proper operating condition.
11. For vehicles with Automatic Traction Control (ATC),
the ATC function must be disabled (ATC indica-
tor lamp should be ON) prior to performing any
vehicle maintenance where one or more wheels
on a drive axle are lifted off the ground and
moving.
OPERATION & LEAKAGE TESTS
GENERAL
A change in vehicle braking characteristics or a low
pressure warning may indicate a malfunction in one or
the other brake circuit, and although the vehicle air brake
system may continue to function, the vehicle should
not be operated until the necessary repairs have been
made and both braking circuits, including the pneumatic
and mechanical devices are operating normally. Always
check the vehicle brake system for proper operation after
performing brake work and before returning the vehicle
to service.
OPERATION TEST
1. Apply and release the brakes several times and check
for prompt application and release at each wheel. If a
prompt reaction is noted at some, but not all wheels, test
the antilock modulator between the ATR-1
™ valve and
the brake chamber for proper operation. If a sluggish
response is noted at all wheels, inspect for a kinked
or obstructed air line leading to or from the ATR-1
™
valve. If a complete release of the brakes is noted at
some, but not all wheels, test the antilock modulator
between the ATR-1
™ valve and the brake chamber for
proper operation. If an incomplete release is noted at
all wheels, inspect for a kinked or obstructed air line
leading to or from the ATR-1
™ valve.
Note: The ATR-1 ™ valve’s differential pressure can
be checked by applying 10 psi to the service port
and noting the pressure registered at the delivery
port. Subtract delivery port pressure from the 10 psi
service pressure to obtain the differential. Compare
the measured differential with the pressure specifi ed for
the ATR-1
™ valve’s part number (see the l.D. washer
also for the differential). NOTE: For ATR-1 ™ valves
not incorporating a relay piston return spring(14) the
measured differential should be approximately 4 psi.
When a spring is in use, the differential will be higher.
2. Disconnect the ATR-1 ™ valve’s two pin solenoid
connector from the controller wire harness. Apply the
probes of a volt-ohm meter to the connector leading
to the solenoid and note the resistance of the solenoid
is between 10 and 12 ohms. If resistance other than
this is noted, replace the ATR-1
™ valve.
3. Apply and remove vehicle power (12 vdc) to the two pin
connector half leading to the ATR-1 ™ valve’s (solenoid)
while observing the brake chambers. Note that a brake
application is made and held while power is applied
to the ATR-1
™ valve’s solenoid and that it is released
when power is removed.
LEAKAGE TESTS
1. Build the air system pressure to governor cut-out. Apply
a soap solution to the exhaust port. The leakage noted
should not exceed a 1” bubble in less than 3 seconds.
2. Make and hold a full brake application and apply a soap
solution to the exhaust port and around the cover where
it joins the body. The leakage noted should not exceed
a 1” bubble in less than 3 seconds at the exhaust port.
If the ATR-1 ™ valve fails to function as described, or
leakage is excessive, it should be replaced with a new
or genuine Bendix remanufactured unit or repaired
using a genuine Bendix maintenance kit piece number
109368, available at any authorized parts outlet.
VEHICLE PREPARATION
1. Park the vehicle on a level surface and block the wheels
and/or hold the vehicle by means other than the air
brakes.
2. Drain the air pressure from all vehicle reservoirs.
REMOVAL
1. Identify and mark or label all electrical wiring harnesses
and air lines and their respective connections on the
assembly to facilitate ease of installation.
2. Disconnect the air lines and wire harnesses.
3. Remove the controller and valve assembly from the
vehicle.