®
Bendix® ATR-1™ AntiLock Traction Relay Valve
SD-13-4811
CONTROLLER
MOUNTING HOLES (4)
MOUNTING
BRACKET
SERVICE
PORT
BODY
SUPPLY
PORT
COVER PLATE FOR
REMOTE MOUNT
REMOTE MOUNT ATR-1™ RELAY VALVE
FIGURE 1 - ATR-1™ ANTILOCK TRACTION RELAY VALVE
DESCRIPTION
The ATR-1™ antilock traction relay is a specialized air brake
valve developed for use on Bendix antilock/traction equipped
vehicles.
It is essentially three separate valves working in combination
in a single housing. An R-14™ style service relay is the base
valve and is fitted with a modified cover containing a double
check valve and a traction control solenoid. The ATR-1™ valve
contains both air and electric components to provide the
service braking and traction control (differential braking)
functions. A Bendix antilock traction controller can be
mounted to the ATR-1™ valve or a cover plate can be installed
and the antilock controller mounted elsewhere on the vehicle.
When an ATR-1™ valve is combined with an antilock traction
controller the resulting assembly is referred to as an antilock
traction assembly.
The ATR-1™ valve replaces the standard relay valve used to
control the rear axle service brakes and performs the standard
relay function. Like the standard relay valve it replaces, the
ATR-1™ valve (sometimes with attached antilock controller)
TRACTION CONTROL
SOLENOID
UNDRILLED
“CON” PORT
DELIVERY
PORT (4)
2 PIN SOLENOID
CONNECTOR
is normally mounted near the service brakes it serves. A
mounting bracket, furnished with the valve, permits either
frame or cross member mounting. All air connections on
the ATR-1™ valve are identified for ease of installation. The
letter identification and air line connections are shown below
for reference.
EMBOSSED
ATR-1™ VALVE AIR CONNECTION IDENT.
Supply (to reservoir) SUP
Delivery (to brake Chamber) DEL
Service (to brake valve rear delivery) SER
Control (not drilled or threaded on ATR-1™ valve) CON
The ATR-1™ valve is part of the R-12™ family of relay valves
which includes the R-12™, R-14™, BP-R1™, AR-1™.
The internal components of the relay portion of all of these
valves are interchangeable with the R-12™ valve and therefore
the same basic components are used to service all of them.
The ATR-1™ valve is available with various crack pressures
to accommodate specific applications, however the standard
is 4 psi.
SUPPLY
PORT
1
CONTROLLER
ATR-1™ ANTILOCK
TRACTION RELAY
VALVE
FIGURE 2 - ANTILOCK TRACTION ASSEMBLY
OPERATION
GENERAL
Because the ATR-1™ is essentially a relay valve, the following
description of operation refers to its function in the vehicles
air brake system and does not address all of the separate
antilock components and their operation. For a description
of antilock operation, refer to the appropriate Service Data
Sheet covering the electronic controller used with the
ATR-1™ valve.
SERVICE BRAKES APPLYING (FIGURE 4)
Reservoir air pressure is present at the supply port and flows
through internal body and cover passages to the supply of
the normally closed (NC) traction control solenoid.
Brake application air enters the ATR-1™ valve’s service port
and is conducted to the single check valve. The check valve
diaphragm flexes in response to application pressure and
seals the passage to the open exhaust of the traction
solenoid. Air flows through the service piston then through
the center of the blend back and through a passage in the
cover to the top of the service relay piston. In response to air
pressure, the relay piston moves into contact with the
exhaust portion of its inlet and exhaust valve. With the
exhaust passage sealed, continued movement of the piston
unseats the inlet portion of the inlet and exhaust valve,
allowing supply air from the reservoir to flow out the ATR-1
valve’s delivery ports to the brake chambers.
™
SOLENOID
CONNECTOR
BLEND BACK
PISTON
SUPPLY
TRACTION CONTROL
SOLENOID
SERVICE
DOUBLE
CHECK VALVE
RELAY PISTON
INLET-EXHAUST
VALVE
DELIVERY
FIGURE 3 - ATR-1™ ANTILOCK TRACTION ASSEMBLY
2
EXHAUST
CONTROLLER
TRACTION
SOLENOID
BRAKE
VALVE
CHECK VALVE
RELAY PISTON
REAR AXLE
RESERVOIR
FIGURE 4 - SERVICE BRAKE APPLICATION
SERVICE BRAKES HOLDING (FIGURE 5)
The air pressure being delivered to the brake chambers is
also present beneath the relay piston.
When the air pressure above and below relay piston is equal,
the piston moves slightly allowing the inlet valve to return to
CONTROLLER
INLET EXHAUST
MODULATOR
SPRING BRAKE
its seat. The exhaust valve remains closed. With both the
inlet and exhaust valves closed, air pressure in the brake
chambers is held stable and neither increases nor decreases.
TRACTION
SOLENOID
RELAY PISTON
REAR AXLE
RESERVOIR
FIGURE 5 - SERVICE BRAKES HOLDING
BRAKE
VALVE
CHECK VALVE
INLET EXHAUST
MODULATOR
SPRING BRAKE
3
CONTROLLER
TRACTION
SOLENOID
RELAY PISTON
REAR AXLE
RESERVOIR
FIGURE 6 - SERVICE BRAKES RELEASING
SERVICE BRAKES RELEASING (FIGURE 6)
When the brake application is released, air from above the
relay piston flows back through the blend back and service
pistons to the foot brake valve and is exhausted. As air
pressure is reduced above the relay piston, pressure beneath
it lifts the piston away from the exhaust valve and opens the
exhaust passage. Air from the service brake chambers
returns to the ATR-1™ valve and flows out the open exhaust.
BRAKE
VALVE
CHECK VALVE
INLET EXHAUST
MODULATOR
EXHAUST
SPRING BRAKE
TRACTION CONTROL SERVICE APPLICATION
(FIGURE 7)
GENERAL
While under the control of an antilock traction controller, the
ATR-1™ valve’s solenoid is able to initiate a brake application
that allows the traction system to control wheel spin upon
acceleration under 25 mph. When wheel spin is detected
CONTROLLER
TRACTION
SOLENOID
RELAY PISTON
REAR AXLE
RESERVOIR
FIGURE 7 - TRACTION CONTROL BRAKE APPLICATION
4
BRAKE
VALVE
CHECK VALVE
INLET EXHAUST
MODULATOR
SPRING BRAKE
BRAKE
REAR AXLE
MODULATOR
MODULATOR
BRAKE
REAR AXLE
EXCITER
ANTILOCK
™
MODULATOR
AT-30
TRACTION ASSY.
(ECM)
ENGINE CONTROL MODULE
MODULATOR
VALVE
BRAKE
SPEED SENSOR
EXCITER
SPEED SENSOR
MODULATOR
TRAILER ABS
(IF SO EQUIPPED)
TRACTION DASH LAMP
TRACTION SWITCH
ANTILOCK DASH LAMP
RETARDER SWITCH
FIGURE 8 - PARTIAL ANTILOCK TRACTION SYSTEM SCHEMATIC
BRAKE
CHAMBER
5
and the vehicle is stopped, or moving at any speed up to 25
mph, the antilock traction controller instantly energizes the
™
solenoid in the ATR-1
valve which then applies air to each
of the rear axle modulators as shown in figure 8. The
modulators are equipped with solenoid valves also and
because they are also controlled by the controller, the
solenoid valves in the appropriate modulator are opened and
closed to gently pump the brake on the spinning wheel only.
This brake application, to the spinning wheel, forces the
differential to drive the stationary or slowly spinning wheel.
OPERATION
Reservoir air pressure is constantly present at the traction
solenoid. When the electronic controller detects wheel spin
it energizes the solenoid and in response the solenoid opens
momentarily. While the solenoid is open, air is delivered
through internal passages to the double check valve. The
check valve diaphragm flexes in response and seals the
passage to the open exhaust of the brake valve. Once past
the double check valve, air from the solenoid flows through
the rest of the valve in the same manner as a normal service
brake application and air is delivered out the delivery ports
of the ATR-1
™
valve.
When the electronic controller de-energizes the solenoid,
air between the solenoid and the double check valve returns
to the solenoid and is exhausted. Air between the relay piston
and double check valve is exhausted at the brake valve while
delivery pressure is exhausted at the main ATR-1™ valve’s
exhaust port.
PREVENTIVE MAINTENANCE
Important: Review the warranty policy before
performing any intrusive maintenance procedures. An
extended warranty may be voided if intrusive
maintenance is performed during this period.
Because no two vehicles operate under identical conditions,
maintenance intervals will vary. Experience is a valuable guide
in determining the best maintenance interval for a vehicle.
GENERAL
Perform the tests and inspections presented at the
prescribed intervals. If the ATR-1™ valve fails to function as
described, or leakage is excessive, it should be repaired or
replaced with a new or genuine Bendix remanufactured unit,
available at any authorized parts outlet.
EVERY 3 MONTHS, 25,000 MILES OR 900 OPERATING
HOURS
1. Remove any accumulated contaminates and visually
inspect the exterior for excessive corrosion and physical
damage.
2. Inspect all air lines connected to the ATR-1™ valve for
signs of wear or physical damage. Replace as necessary.
3. Test air line fittings for excessive leakage and tighten or
replace as necessary.
4. Perform the Leakage Test described in this manual.
EVERY YEAR, 100,000 MILES, OR 3,600 OPERATING
HOURS
1. Perform the Operation and Leakage Tests described in
this manual.
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.
™
6
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.
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 specified 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 cutout. 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.
™
INSTALLATION
1. Install the assembled unit on the vehicle.
2. Reconnect all air lines and wire harnesses to the unit
using the identification made during REMOVAL step 1.
3. After installing the unit, perform the OPERATION &
LEAKAGE TESTS for the air valve before placing the
vehicle in service.
7
35
2
34
33
32
1
PRIOR INTERNAL
COMPONENT
CONFIGURATION
12
16
31
30
29
28
27
26
25
24
Assembly
of items
3
18
21
19
20
17
4
29-35
15
35
34
14
Key Description
22
1 ECU Control
2 Bolts (4)
3 Cover
4 Base
5 Retaining Ring
6 Exhaust Cover
7 O-Ring
8 O-Ring
9 Valve Spring
10 Valve Retainer
11 Valve Assembly
12 Cap Screws (2)
13 Nuts and Washers (2)
14 Lock Washers (2)
15 Bracket
16 Cap Screws (2)
17 O-Ring
18 O-Ring
Key Description
19 Relay Piston
20 Piston Spring (if used)
21 O-Ring
22 Retaining Ring
23 Check Valve*
24 O-Ring
25 Inlet Seat*
26 Check Valve Seat
27 O-Ring
28 Check Valve
29 Spring Seat
30 Spring
31 Inlet Seat
32 O-Ring
33 O-Ring
34 O-Ring
35 Alternate Plug*
36 Bolts (2)
23
22
11
10
9
8
7
13
6
5
FIGURE 9 - ANTILOCK TRACTION ASSEMBLY EXPLODED VIEW
8
* Note: For new style ATR-1™ valves either both
items 23 - 25, or item 35 will be present.
DISASSEMBLY
PREPARATION FOR DISASSEMBLY
1. Remove all air fittings and plugs from the valve.
2. Mark the relationship of the valve cover(3) to the body(4)
and, if the valve is equipped with a mounting bracket(15),
mark the relationship of the bracket to the cover and
body(4).
3. Mark the relationship of the electronic controller(1) to
the cover(3).
DISASSEMBLY
The following disassembly and assembly procedure is
presented for reference purposes only. Instructions packaged
with repair and maintenance kits should always be followed
instead of the instructions presented here.
Then, depending on the internal configuration:
12a. Remove check valve seat(23), with o-rings(27 & 28).
Remove o-rings(27 & 28) from the check valve seat.
Then Remove the check valve(24), guide(25), and
spring(26).
OR,
12b. Remove plug(35), with o-ring(34).
13. Remove the inlet seat(29) with o-rings(30 & 31), then
remove o-rings(30 & 31) from the inlet seat(29).
14. Remove the blend back piston(32) from the valve cover(3).
Remove both o-rings(33 & 34) and the piston stop
ring(35). Note: The piston stop ring may have to be
removed from the cover(3) rather than the piston(32).
15. Do not disassemble the ATR-1™ valve any further than
described here.
CAUTION: The valve may be lightly clamped in a bench
vise during disassembly, however, over clamping will
result in damage to the valve and result in leakage
and/or malfunction. If a vise is to be used, position the
valve so that the jaws bear on the supply ports on
opposing sides of the valve body.
1. Remove and retain the four cap screws(2) that secure
the electronic controller(1) to the cover(3), then separate
and retain the controller(1), from the cover(3). Note: In
some instances a controller, Item 1, will not be present
and only a cover plate will be noted. Remove the cover
plate in the same manner described for the controller.
2. While holding the exhaust cover(6), remove the retaining
ring(5) that secures it to the body(4).
3. Remove the exhaust cover(6) along with both o-rings(7
& 8).
4. Remove the valve spring(9), valve retainer(10), and the
valve assembly(11) from the body(4).
5. Remove and retain the two long cap screws(12) and
nuts(13) that secure the cover(3) to the body(4).
6. Remove and retain the two cap screws and lock
washers(14) that secure the bracket(15) to the cover(4),
then remove and retain the bracket.
7. Remove and retain the two short cap screws(16) that
secure the cover(3) to the body(4).
8. Separate the cover(3) from the body(4), then remove the
sealing ring(17) and o-ring(18).
9. Remove the relay piston(19) and relay piston spring(20)
from the body(4). NOTE: The relay piston spring, item
14 is not used in all valves.
10. Remove the o-ring(21) from the relay piston(19).
11. Remove the retaining ring(22).
CLEANING & INSPECTION
1. Using mineral spirits or an equivalent solvent, clean and
thoroughly dry all metal parts. Do not damage bores
with metal tools.
2. Wash all retained, nonmetallic components in a soap
and water solution making certain to rinse and dry
thoroughly.
3. Inspect the interior and exterior of all metal parts that
will be reused for severe corrosion, pitting and cracks.
Superficial corrosion and/or pitting on the exterior portion
of the body(4) and cover(3) is acceptable. Replace the
entire valve if the interior of the body or cover exhibit
signs of corrosion or pitting.
4. Inspect each nonmetallic component for cracks, wear
or distortion. Replace the entire valve if these conditions
are found.
5. Inspect the bores of both the body(4) and cover(3) for
deep scuffing or gouges. Replace the entire valve if ether
are found.
6. Make certain the air channel running between the top
surface of the body(1) and its supply port is clear and
free of obstruction.
7. Make certain all air channels and exhaust passages in
the valve cover(3) are clear and free of obstruction.
8. Inspect the pipe threads in the body(4) and valve cover(3).
Make certain they are clean and free of thread sealant.
9. Inspect the relay piston spring(20) for signs of corrosion,
pitting and cracks. Replace as necessary.
10. Inspect all air line fittings for corrosion and replace as
necessary. Make certain to remove all old thread sealant
before reuse.
9
1234
1234
1234
1234
ASSEMBLY
1. Prior to assembly, lubricate all o-rings, seals, and pistons,
as well as body and cover bores, using silicone lubricant.
2. Install the piston stop ring(35), then both the large and
small diameter o-rings(33 & 34) on the blend back
piston(32), then insert the small diameter of the
proportioning piston(32) into the bore in the cover(3). Do
not cut or pinch the o-rings.
O.D.
W
I.D.
O-Ring Identification
Key Description Qty. I.D. O.D. W
7 O-Ring 1 0.862 1.068 0.103
8 O-Ring 1 1.424 1.63 0.103
18 O-Ring 1 3.487 3.693 0.103
21 O-Ring 1 3.234 3.512 0.139
27 O-Ring 1 1.362 1.568 0.103
28 O-Ring 1 1.114 1.254 0.07
30 O-Ring 1 1.356 1.496 0.07
31 O-Ring 1 1.176 1.316 0.07
33 O-Ring 1 1.112 1.318 0.103
34 O-Ring 1 0.737 0.943 0.103
(O-rings available in maintenance kit #109368.)
3. Install the small and large diameter o-rings (30 & 31) on
the inlet seat(29) then insert the inlet seat into the bore
in the cover(2).
Depending on the configuration/kit being installed:
4a. Install the small and large diameter o-rings (27 & 28) on
the check valve seat(23). Then install the spring(26) on
the inlet seat(29) so that the small diameter fits over
and around the air passage through the center of the
inlet seat. Install the check valve(24) and valve guide(25)
in the check valve seat(23). Note; The check valve must
be installed so that the top hat portion fits into the valve
seat(23). Install the valve guide(25) so that its flange
contains (surrounds) the coils of the large end of the
spring(26), when the valve seat (23) is installed in the
cover(3). Use a small amount of grease to hold these
parts in the valve seat (23). Install the assembled valve
seat(23) with the check valve and valve guide(24 & 25)
into the cover(3) bore and while holding it in place install
the retaining ring(22). Make certain the retaining ring is
fully seated in its groove.
OR,
4b. Install the o-ring(34) onto the plug(35). Install into the
cover(3) bore and while holding it in place install the
retaining ring(22). Make certain the retaining ring is fully
seated in its groove.
5. Install the valve retainer(10) on the inlet and exhaust
valve(11) so that the flange of the retainer(10) surrounds
the rubber portion of the valve. Install the inlet and exhaust
valve in the body(4).
6. Install the inlet and exhaust valve return spring(9) in the
body(4).
7. Install the large and small diameter o-rings(7 & 8) in the
exhaust cover(6), then install the exhaust cover in the
body(4) taking care not to damage the o-rings. Hold the
exhaust cover in place.
8. While depressing the exhaust cover(6), install the
retaining ring(5) in the body(4). Make certain the
retainer(5) is fully seated in its groove in the body.
9. If the valve was equipped with a relay piston return
spring(20), install the spring in the body, large diameter
first.
10. Using lubricant to hold them in place, install the large
and small sealing rings(18 & 17) on the cover(3).
11. Install the o-ring(21) on the relay piston(19), then install
the piston in the body(4).
12. Note the relationship marks made prior to disassembly,
then install the cover(3) on the body(4). Secure the cover
on the body using the two, short cap screws(16). Again,
noting the relationship marks, secure the bracket(15)
on the cover(3) and body(4) and using the two long cap
screws(12) and two nuts and washers(13). Torque the
four cap screws to 120 to 150 lb. in.
13. Install the two cap screws(14) that secure the bracket(15)
to the cover(3) and torque to 180-220 pound inches.
14. Noting the relationship marks made during disassembly,
secure the controller(1) or cover plate to the cover(3)
using the four cap screws(2). Torque the four cap screws
to 50-80 pound inches.
15. Install all air line fittings and plugs making certain thread
sealing material does not enter the valve.
16. Install the rebuilt valve on the vehicle and perform the
OPERATION AND LEAKAGE TESTS before placing the
vehicle in service.
10
NOTES
11
12
BW1794 © 2004 Bendix Commercial Vehicle Systems LLC 10/2004 Printed in U.S.A. All rights reserved.
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