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7

WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO 

AVOID

PERSONAL INJURY OR DEATH:

When working on or around a vehicle, the following
general precautions should be observed at all times.

1.

Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses.

2.

Stop the engine and remove ignition key when
working under or around the vehicle.  When
working in the engine compartment, the engine
should be shut off and the ignition key should be
removed. Where circumstances require that the
engine be in operation, EXTREME CAUTION should
be used to prevent personal injury resulting from
contact with moving, rotating, leaking, heated or
electrically charged components.

3.

Do not attempt to install, remove, disassemble or
assemble a component until you have read and
thoroughly understand the recommended
procedures.  Use only the proper tools and observe
all precautions pertaining to use of those tools.

4.

If the work is being performed on the vehicle’s air
brake system, or any auxiliary pressurized air
systems, make certain to drain the air pressure from
all reservoirs before beginning ANY work on the
vehicle.  If the vehicle is equipped with an AD-IS

air dryer system or a dryer reservoir module, be
sure to drain the purge reservoir.

5.

Following the vehicle manufacturer’s
recommended procedures, deactivate the electrical
system in a manner that safely removes all
electrical power from the vehicle.

6.

Never exceed manufacturer’s recommended
pressures.

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

®

 replacement parts,

components and kits. Replacement hardware,
tubing, hose, fittings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifically 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 specifically 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 Antilock Traction Control (ATC),

the ATC function must be disabled (ATC indicator
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.

To properly test the function of the ATR-2

 valve, a pair of

test gauges or gauges of known accuracy must be used.

OPERATION TEST

1. Drain air pressure from all vehicle reservoirs.

FIGURE 11 - TRACTION CONTROL BRAKE APPLICATION

CONTROLLER

BRAKE

VALVE

CHECK VALVE

RELAY PISTON

INLET EXHAUST

REAR AXLE

RESERVOIR

TRAILER SUPPLY

PROP. PISTON

TRACTION

SOLENOID

INLET EXHAUST

SERVICE BRAKE

MODULATOR

Summary of Contents for ATR-2 ANTILOCK TRACTION VALVE

Page 1: ...of times antilock is actually needed Like the standard relay valve it replaces the ATR 2 valve and its attached antilock controller is normally mounted near the service brakes it serves A mounting br...

Page 2: ...gh the service piston then through the center of both the blend back and proportioning pistons to the inlet and exhaust valve Flowing around the inlet valve application air moves through a passage in...

Page 3: ...E RELAY PISTON INLET EXHAUST MODULATOR SERVICE BRAKE REAR AXLE RESERVOIR TRAILER SUPPLY PROPORTIONING PISTON INLET EXHAUST CONTROLLER BRAKE VALVE BRAKE VALVE CHECK VALVE RELAY PISTON INLET EXHAUST SER...

Page 4: ...d a subsequent increase in brake chamber pressure until service application pressure exceeds approximately 30 psi Service applications above this pressure will result in a proportioned increase of the...

Page 5: ...d in the ATR 2 valve which then applies air to each of the rear axle modulators as shown in Figure 12 The modulators are equipped with solenoid valves FIGURE 7 BOBTAIL TRAILER SERVICE BRAKES APPLYING...

Page 6: ...valve is exhausted at the brake valve while delivery pressure is exhausted at the main ATR 2 valve s exhaust port PREVENTIVE MAINTENANCE GENERAL Perform the tests and inspections presented at the pres...

Page 7: ...re certain all system pressure has been depleted 8 Use only genuine Bendix replacement parts components and kits Replacement hardware tubing hose fittings etc must be of equivalent size type and stren...

Page 8: ...rtial REAR AXLE BRAKE MODULATOR MODULATOR REAR AXLE BRAKE SPEED SENSOR EXCITER BRAKE VALVE AT 30BP ANTILOCK TRACTION ASSY SPEED SENSOR EXCITER BRAKE CHAMBER MODULATOR ENGINE CONTROL MODULE ECM RETARDE...

Page 9: ...gins to rise above the initial pressure noted in step 6 The rise of delivery pressure should be at a proportioned rate of approximately 3 to 1 At 70 psi service pressure delivered pressure should be 1...

Page 10: ...then remove and retain the spring cage 23 from the valve cover 2 15 Use shop air at the control port to extract the blend back piston 24 from the valve cover 2 Retain the piston 24 but remove and disc...

Page 11: ...Long Cap Screw 2 11 O Ring 1 12 Relay Piston 1 13 O Ring 1 14 Relay Piston Spring if used 1 15 RetainingRing 1 16 Check Valve Seat 1 17 Check Valve 1 18 Valve Guide 1 19 Spring 1 20 O Ring 1 21 O Rin...

Page 12: ...all the inlet and exhaust valve return spring 7 in the body 1 18 Install the large and small diameter o rings 5 6 in the exhaust cover 4 then install the exhaust cover in the body 1 taking care not to...

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