BENDIX ATR1DC ANTILOCK TRACTION RELAY User manual

1
®
SD-13-4811A
DESCRIPTION
TheATR-1DC™antilocktractionrelay valveis aspecialized
airbrakevalve developedforuseonBendixantilock/traction
equipped vehicles. TheATR-1DC™valve can be used on
straight trucks, buses and tractors. Although this valve, in
combination with the appropriate controller, can be used
in any Bendix antilock traction equipped brake system, it
wasdeveloped forusein systemsthat werebuilttocomply
withFederal regulationseffective 3/1/98.
Itisa combinationoffourseparatevalvesworkinginasingle
housing. ABendix®R-14™service relay is the base valve,
fitted with a modified cover containing two double check
valves and a traction control solenoid. In addition, the
ATR-1DC™valvealsoincorporatesarelaypistondrain,which
continuallyallows systemcontamination tobe drainedfrom
the relay exhaust port. (Refer to Service Data Sheet for
moreinformation.)
The ATR-1DC™valve contains both air and electric
components to provide the service braking and traction
control(differential braking)functions. Thetractionfunction
of theATR-1DC™valve is enhanced to allow coordination
with the air suspension system of a 6x2 vehicle.
ABendixantilock tractioncontroller,suchastheEC-16™or
EC-17™,can bemountedtotheATR-1DC™valveora cover
plate can be installed and the antilock controller mounted
elsewhere on the vehicle. When an ATR-1DC™valve is
combined with an antilock traction controller the resulting
assembly is referred to as a antilock traction assembly or
AT-1DC™.
TheATR-1DC™valvereplacesthestandardrelayvalveused
to control the rear axle service brakes and performs the
standard relay function. Like the standard relay valve it
replaces, the ATR-1DC™valve (sometimes with attached
antilock controller) is normally mounted near the service
brakes it serves. A mounting bracket, furnished with the
valve,permitseither frameor cross membermounting. All
air connections on theATR-1DC™valve are identified with
cast, embossed letters for ease of identification and
installation. Theletter identificationand airlineconnections
areshown belowforreference.
EMBOSSEDATR-1DCAIRCONNECTION IDENT.
Supply (to reservoir) SUP
Delivery (to brake Chamber) DEL
Primary Control (to brake valve rear delivery) 4 1
Secondary Control 4 2
(to brake valve front delivery)
Optional Auxiliary 2 1
(connected to air suspension control)
Bendix®ATR-1DC™AntiLock Traction Relay Valve
MOUNTING
BRACKET
CONTROLLER
MOUNTING HOLES (4)
REMOTEMOUNTATR-1DC™VALVE
TRACTION CONTROL
SOLENOID
SECONDARY
CONTROL
PORT
4 2
(1)
DELIVERY
PORT (4)
2 PIN SOLENOID
CONNECTOR
SUPPLY
PORT
(2)
FIGURE 1 - ATR-1DC™ANTILOCK TRACTION RELAY VALVE
PRIMARY
CONTROL
PORT
4 1
(1)
AUXILIARY
CONTROL
PORT
2 1
(1)
COVER PLATE FOR
REMOTE MOUNT
REVERSE
ANGLE
VIEW

2
ATR-1DC™
ANTILOCK
TRACTION
RELAY
VALVE
EC-16™CONTROLLER
FIGURE 2 - TYPICAL AT-1DC™ANTILOCK TRACTION ASSY.
FIGURE 3 - SECTIONAL AT-1DC™ANTILOCK TRACTION ASSEMBLY
TheATR-1DC™valveispartoftheR-12™familyofrelayvalves
whichincludes theR-12™,R-14™,BP-R1™,AR-1™&ATR-1™
valves. Theinternal componentsofthe relayportion ofallof
thesevalves aresimilarand inmany casesinterchangeable
with the R-12™valve and therefore the same basic
componentsareused toserviceallofthem. TheATR-1DC™
valve is available with various crack pressures to
accommodatespecificapplications, howeverthestandard
is 4 psi, achieved without any added spring.
OPERATION
GENERAL
WhiletheATR-1DC™valveisan antilock-tractionrelayvalve
itstruefunction isthat of anair brakerelayvalve. Because
the ATR-1DC™is essentially a relay valve, with a traction
control function, the following description of operation
describes its operation as a relay valve and its function in
the traction control system. The full operation of the
antilocksystemandseparateantilockcomponentsandtheir
operation is not addressed in this publication. For a
description of antilock operation, refer to the appropriate
ServiceDataSheet coveringtheelectronic controllerused
withtheATR-1DC™valve (e.g.SD-13-4785for theEC-16™
electroniccontroller,orSD-13-4788fortheEC-17™electronic
controller). Other useful information on antilock system
componentsmaybedownloadedfromwww.bendix.com.For
example: SD-13-4793 (M-21™and M-22™antilock
modulators), SD-13-4870 (M-32™and M-32QR™antilock
modulators),SD-13-4754(WS-20™wheel speedsensors),
andSD-13-4860 (WS-24™wheelspeed sensors).
SERVICEBRAKES -APPLYING
Reservoir air pressure is present at the supply port (SUP)
and at the relay inlet and exhaust valve. Reservoir air
pressure also flows from the supply port through internal
TRACTION CONTROL SOLENOID
SUPPLY PORT
SECONDARY
SERVICE PORT
DOUBLE
CHECK VALVES
DELIVERY
PORT
EXHAUST PORT
RELAY PISTON
INLET-EXHAUST
VALVE
BLEND BACK
PISTON
SOLENOID
CONNECTOR
BRAKE VALVE
(SHOWING
DELIVERY AIR
LINES ONLY)
AIR BAG
BRAKE
CHAMBER
TONE RING
EC-16™OR EC-17™
CONTROLLER
WHEEL SPEED
SENSOR
PRIMARY
SERVICE PORT
RELAY PISTON
SPRING
(IF USED)
RESERVOIR

3
FIGURE 4 - SERVICE BRAKE APPLICATION
FIGURE 5 - SERVICE BRAKES HOLDING
bodyandcoverpassagestothesupplyofthenormallyclosed
(NC)tractioncontrol solenoid.
Brakeapplicationair fromboththerearandfrontaxlecircuits
ofthe brakevalveenters theATR-1DC™valve's primaryand
secondarycontrol ports. Secondarycontrolpressureflexes
doublecheckvalve diaphragm “A”causing it tosealthe air
passage leading to the solenoid and opening the passage
leadingto doublecheckvalve “B”. Primarycontrol airflows
to double check valve diaphragm “B”. Because primary
control pressure, from the foot valve, is 2 to 4 psi greater
thansecondarycontrol, doublecheck valve diaphragm“B”
flexes in response to primary control and seals the air
passage leading to the secondary control. Air flows past
doublecheckvalvediaphragm“B”andthroughapassagein
thecoverto thetop oftheservice relaypiston. In response
TRACTION CONTROL SOLENOID
SUPPLY PORT
SECONDARY
SERVICE PORT
DOUBLE
CHECK VALVE “A”
DELIVERY
PORT
EXHAUST PORT
RELAY PISTON
INLET-EXHAUST
VALVE
BLEND BACK
PISTON
SOLENOID
CONNECTOR
AIR BAG
BRAKE
CHAMBER
TONE RING
EC-16™OR EC-17™
CONTROLLER
WHEEL SPEED
SENSOR
PRIMARY
SERVICE PORT
DOUBLE
CHECK VALVE
“B”
TRACTION CONTROL SOLENOID
SUPPLY PORT
SECONDARY
SERVICE PORT
DOUBLE
CHECK VALVE “A”
DELIVERY
PORT
EXHAUST PORT
RELAY PISTON
INLET-EXHAUST
VALVE
BLEND BACK
PISTON
SOLENOID
CONNECTOR
AIR BAG
BRAKE
CHAMBER
TONE RING
EC-16™OR EC-17™
CONTROLLER
WHEEL SPEED
SENSOR
PRIMARY
SERVICE PORT
DOUBLE
CHECK VALVE
“B”
BRAKE VALVE
HELD IN
APPLIED
POSITION
BRAKE VALVE
(SHOWING
DELIVERY AIR
LINES ONLY)

4
FIGURE 6 - SERVICE BRAKES RELEASING
toair pressure,therelaypistondrainvalveflexes andseals
the drain passage leading to the relay exhaust.
Simultaneouslythe relaypiston movesintocontactwiththe
exhaust portion of its inlet and exhaust valve. With the
exhaustpassage sealed,continuedmovementofthe piston
unseats the inlet portion of the inlet and exhaust valve,
allowingsupplyairfromthereservoirtoflowouttheATR-1DC™
valve'sdelivery portstothebrakechambers.
SERVICE BRAKES - HOLDING
Air pressure being delivered to the brake chambers is also
presentbeneath therelay piston. Whenair pressureabove
and below the relay piston is equal, the piston moves
FIGURE 7 - SERVICE BRAKES - APPLYING (PRIMARY CIRCUIT DELIVERY FAILED)
TRACTION CONTROL SOLENOID
SUPPLY PORT
SECONDARY
SERVICE PORT
DOUBLE
CHECK VALVE “A”
DELIVERY
PORT
EXHAUST
PORT
RELAY PISTON
INLET-EXHAUST
VALVE
BLEND BACK
PISTON
SOLENOID
CONNECTOR
AIR BAG
BRAKE
CHAMBER
TONE RING
EC-16™OR EC-17™
CONTROLLER
WHEEL SPEED
SENSOR
PRIMARY
SERVICE PORT
DOUBLE
CHECK VALVE
“B”
BRAKE VALVE
(RELEASED)
TRACTION CONTROL SOLENOID
SUPPLY PORT
SECONDARY
SERVICE PORT
DOUBLE
CHECK VALVE “A”
DELIVERY
PORT
EXHAUST PORT
RELAY PISTON
INLET-EXHAUST
VALVE
BLEND BACK
PISTON
SOLENOID
CONNECTOR
AIR BAG
BRAKE
CHAMBER
TONE RING
EC-16™OR EC-17™
CONTROLLER
WHEEL SPEED
SENSOR
PRIMARY
SERVICE
CONTROL LINE
FAILURE
DOUBLE
CHECK VALVE
“B”
BRAKE VALVE
(SHOWING
DELIVERY AIR
LINES ONLY)

5
FIGURE 8 - TRACTION CONTROL BRAKE APPLICATION
slightly allowing the inlet valve to return to its seat. The
exhaust valve remains closed. With both the inlet and
exhaustvalvesclosed, airpressurein thebrakechambers
is held constant and neither increases nor decreases.
SERVICEBRAKES - RELEASING
Whenthebrake applicationisreleased, airfromabove the
relaypiston,flows backtoand pastdoublecheck valve“B”
and returns to the exhaust of the brake valve. Air on the
otherside ofdouble checkvalve“B”andfromdoublecheck
valve“A”also returnstothe exhaustof the brakevalve. As
air pressure above the relay piston is released the natural
resilience of the relay piston drain valve causes it to return
toitsoriginal positionwhich opensthedrain passagein the
relay piston. With the piston drain open, gravity allows
contaminationtoflow outthe relayvalveexhaust.
Asair pressureisreduced abovethe relaypiston, pressure
beneath lifts the piston away from the exhaust valve and
opens the exhaust passage. Air from the service brake
chambersreturns totheATR-1DC™valve andflowsout the
openexhaust.
SERVICEBRAKES –APPLYING (PRIMARY CIRCUIT
FAILED)
Intheeventtherearaxledeliverylinefromthebrake valveis
broken, air from the brake valve’s front axle delivery circuit
will enter the secondary control port. Secondary control
pressureflexesdouble checkvalve diaphragm“A”causing
ittosealtheairpassageleadingtothesolenoidandopening
thepassageleadingtodoublecheckvalve“B”. Doublecheck
valvediaphragm“B”flexesin responsetosecondary control
pressure and seals the air passage leading to the primary
control port and primary delivery circuit of the brake valve.
Airflowspastdoublecheckvalvediaphragm“B”and through
apassage inthecovertothe topof theservice relaypiston.
Inresponsetoairpressure,therelaypistondrainvalveflexes
and seals the drain passage leading to the relay exhaust.
Simultaneouslythe relaypiston movesintocontactwiththe
exhaust portion of its inlet and exhaust valve. With the
exhaustpassage sealed,continuedmovementofthe piston
unseats the inlet portion of the inlet and exhaust valve,
allowingsupplyairfromthereservoirtoflowouttheATR-1DC™
valve'sdelivery portstothebrakechambers.
TRACTIONCONTROL- SERVICEAPPLICATION
GENERAL
Whileunder thecontrol ofan antilocktractioncontroller, the
ATR-1DC™valve's solenoid is able to initiate a brake
applicationthatallows the traction systemtocontrol wheel
spinduring accelerationunder 25mph. Whenwheelspinis
detectedand thevehicleis stopped,ormovingatany speed
up to 25 mph, the antilock traction controller instantly
energizes the solenoid in theATR-1DC™valve which then
applies air to each of the rear axle modulators as shown in
Figure 8. The modulators are also equipped with solenoid
valves and because the controller also controls them, the
solenoidvalvesintheappropriatemodulatorareopenedand
closedto gentlypump thebrake onthespinningwheelonly.
This brake application, to the spinning wheel, forces the
differentialtodrive thestationary orslowlyspinning wheel.
TRACTION CONTROL SOLENOID
SUPPLY PORT
SECONDARY
SERVICE PORT
DOUBLE
CHECK VALVE “A”
DELIVERY
PORT
EXHAUST PORT
RELAY PISTON
INLET-EXHAUST
VALVE
BLEND BACK
PISTON
SOLENOID
CONNECTOR
AIR BAG
BRAKE
CHAMBER
TONE RING
EC-16™OR EC-17™
CONTROLLER
WHEEL SPEED
SENSOR
PRIMARY
SERVICE PORT
DOUBLE
CHECK VALVE
“B”
BRAKE VALVE
(SHOWING
DELIVERY AIR
LINES ONLY)

6
FIGURE 9 - PARTIAL ANTILOCK TRACTION SYSTEM SCHEMATIC
BRAKE
VALVE
(SHOWING DELIVERY
LINES ONLY)
AT-1DC
™
ANTILOCK TRACTION ASSY.
(EC-16
™
OR EC-17
™
CONTROLLER + ATR-1DC
™
VALVE)
MODULATOR
MODULATOR
REAR AXLE
BRAKE
REAR AXLE
BRAKE
EXCITER
SPEED SENSOR
EXCITER
SPEED SENSOR
MODULATOR
BRAKE
CHAMBER
ENGINE CONTROL MODULE
(ECM)
TRACTION SWITCH
ANTILOCK DASH LAMP
TRACTION DASH LAMP
RETARDER SWITCH
MODULATOR

7
TheATR-1DC™valvealsohas anauxiliarycontrol portthat
permits coordination of the traction function with an air
suspendedtagaxle ona6x2 vehicle. Theauxiliarycontrol
port(21) connects to the air suspension control valve. If a
traction event occurs and the tag axle is down and loaded
theATR-1DC™valve isabletoreduceair pressurein thetag
axle air bags. Lowering pressure in the tag axle air bags
increasesthe loadingonthedriveaxle andfurther assistsin
eliminatingwheelspin onacceleration.
OPERATION
Reservoir air pressure is constantly present at the traction
solenoid. When the electronic controller detects wheel
spinitenergizes thesolenoid and inresponse thesolenoid
opens momentarily. While the solenoid is open, air is
deliveredthroughinternal passagesto double checkvalve
diaphragm“A”.
Note: If the optional auxiliary port is in use, traction
solenoid air pressure is also delivered to the air
suspension system of the “tag” or non-drive axle.
This signal pressure is used to exhaust some of
the air pressure from the suspension bags on the
tag axle. This causes some of the vehicle weight
(carried by the tag axle) to shift to the drive axle
furtherenhancing thetractioncontrol.
The check valve diaphragm flexes in response and seals
thepassage tothe open exhaustof the secondarydelivery
of the brake valve. Once past double check valve “A”, air
from the solenoid flows to double check valve “B” which
flexes and seals the passage to the open exhaust of the
primary delivery of the brake valve. Air flowing around
doublecheckvalve “B”moves through therest ofthevalve
in the same manner as a normal service brake application
andisdeliveredoutthedeliveryportsoftheATR-1DC™valve
totheantilock modulatorsnear the rearwheels theyserve.
Whenthe electroniccontroller de-energizestheATR-1DC™
valve's traction solenoid, air between the solenoid and the
double check valve “A”, including the air signal sent to the
suspension system through the optional auxiliary port,
returns to the solenoid and is exhausted. Air between
double check valve “A” and “B” is exhausted from the
secondary circuit of the brake valve. Air between the relay
piston and double check valve “B” is exhausted from the
primary circuit of the brake valve. Air in the service brakes
isexhaustedat themainATR-1DC™valve's exhaustport.
PREVENTIVE MAINTENANCE
GENERAL
Perform the tests and inspections presented at the
prescribedintervals. If theATR-1DC™valvefailsto function
asdescribed, orleakageisexcessive,it shouldbe repaired
or replaced with a new or genuine Bendix remanufactured
unit,availableat anyauthorizedparts 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. Inspectall airlinesconnectedtotheATR-1DC™valvefor
signs of wear or physical damage. Replace as
necessary.
3. Testairlinefittings forexcessive leakageandtighten or
replace as necessary.
4. Performthe LeakageTestdescribedin thismanual.
EVERYYEAR, 100,000MILES, OR 3,600OPERATING
HOURS
1. PerformtheOperation andLeakage Tests describedin
this manual.
WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO AVOID
PERSONAL INJURYOR 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
enginebe inoperation, EXTREME CAUTIONshould
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. Useonly theproper toolsand 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 todrainthe air pressurefrom
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
recommendedprocedures, deactivatetheelectrical
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
FIGURE 10 - ATR-1DC™ANTILOCK TRACTION ASSEMBLY EXPLODED VIEW
4
3
56
78
9
10
11
18
19
21
20
24 23
22
26 25
27
28
29
30
31
15
14
13
17
2
1
16
32
33
38
12
39
34
35
36
37
40
13

9
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
lampshould beON) priorto performingany 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
mechanicaldevicesare operatingnormally. Alwayscheck
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 (M-21™or M-22™) between
theATR-1DC™valveand thebrakechamber forproper
operation. Ifa sluggishresponseis notedat allwheels,
inspect for a kinked or obstructed air line leading to or
from theATR-1DC™valve. If a complete release of the
brakes is noted at some, but not all wheels, test the
antilockmodulator (M-21™orM-22™)between theATR-
1DC™valveand thebrakechamberforproperoperation.
If an incomplete release is noted at all wheels, inspect
for a kinked or obstructed air line leading to or from the
ATR-1DC™valve.
Note:TheATR-1DC™valve differentialpressurecanbe
checkedbyapplying10psitotheserviceportandnoting
the pressure registered at the delivery port. Subtract
delivery port pressure from the 10 psi service pressure
to obtain the differential. Compare the measured
differentialwiththe pressurespecifiedfor theATR-1DC™
valve part number (see the l.D. washer also for the
differential). NOTE: For ATR-1DC™valves not
incorporating a relay piston return spring (20) the
measured differential should be approximately 4 psi.
When a spring is in use, the differential will be higher.
2. Disconnect the ATR-1DC™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
between10and 12 ohms. Ifresistanceother than this
isnoted, replacetheATR-1DC™valve.
3. Applyand removevehiclepower (12vdc) tothetwo pin
connectorhalfleadingtotheATR-1DC™valve(solenoid)
whileobserving thebrakechambers. Note thata brake
application is made and held while power is applied to
the ATR-1DC™valve's solenoid and that it is released
whenpowerisremoved.
LEAKAGETESTS
1. Build theair systempressure togovernorcutout. Apply
asoapsolution totheexhaust port. Theleakagenoted
should not exceed a 1" bubble in less than 3 seconds.
2. Makeand holdafullbrakeapplicationandapply asoap
solutionto theexhaust portand aroundthe coverwhere
itjoinsthe body. The leakagenotedshould notexceed
a 1" bubble in less than 3 seconds at the exhaust port.
If theATR-1DC™valvefailsto function asdescribed,or
leakage is excessive, it should be replaced with a new
orgenuineBendix remanufacturedunitorrepairedusing
agenuineBendix repairkit, available atany authorized
parts outlet.
VEHICLEPREPARATION
1. Parkthe vehicleon alevel surfaceandblockthewheels
and/or hold the vehicle by means other than the air
brakes.
2. Drain the air pressure from all vehicle reservoirs.
REMOVAL
1. Identify andmark orlabel allelectricalwiringharnesses
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 (AT-1DC™)
fromthevehicle. Note: The antilockcontrollermay not
bemountedto theATR-1DC™valve. Refer to Figure1.
INSTALLATION
1. Install the assembled unit on the vehicle.
2. Reconnect all air lines and wire harnesses to the unit
usingtheidentification made duringREMOVALstep 1.
3. After installing the unit, perform the OPERATION &
LEAKAGE TESTS for the air valve before placing the
vehiclein service.

10
DISASSEMBLY
PREPARATIONFOR DISASSEMBLY
1. Removeall airfittingsandplugsfrom thevalve.
2. Mark the relationship of the valve cover (3) to the body
(4)and, ifthe valveis equippedwith amountingbracket
(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.
CAUTION: The valve may be lightly clamped in a bench
viseduring disassembly, however,over clampingwillresult
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.
Removethecover platein the samemanner 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 20 is not used in all valves.
10. Removethe o-ring(21) fromthe relaypiston(19).
11. Removetheretainingring(22). Thenremovecheckvalve
seat(23),with o-rings(27 &28). Removeo-rings (27&
28)fromthe checkvalve seat.
12. Removethecheckvalve(24),guide(25),andspring(26).
13. Remove the inlet seat (29) with o-rings (30 & 31), then
remove o-rings (30 & 31) from the inlet sea (29).
14. Removethe checkvalve seat(32) fromthe valvecover
(3). Remove both o-ring (33).
15. Removethecheckvalve(34),guide(35),andspring(36).
16. Removetheprimaryinletseat(37) witho-rings(38, 39&
40),thenremove o-rings(38, 39&40) fromthe primary
inlet seat (37).
17. DonotdisassembletheATR-1DC™valveanyfurtherthan
described here.
CLEANING & INSPECTION
1. Usingmineral spiritsor anequivalentsolvent,cleanand
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.
Superficialcorrosionand/or pittingontheexteriorportion
ofthe body(4) andcover (3)isacceptable. Replacethe
entire valve if the interior of the body or cover exhibit
signs of corrosion or pitting.
4. Inspect each nonmetallic component for cracks, wear
ordistortion. Replacetheentirevalve iftheseconditions
arefound.
5. Inspect the bores of both the body (4) and cover (3) for
deepscuffingorgouges. Replacetheentirevalveifeither
arefound.
6. Make certain the air channel running between the top
surface of the body (1) and its supply port is clear and
freeof obstruction.
7. Make certain all air channels and exhaust passages in
thevalve cover(3) areclearandfreeofobstruction.
8. Inspectthe pipethreadsin thebody (4)and valvecover
(3). Make certain they are clean and free of thread
sealant.
9. Inspectthe relaypistonspring (20)forsigns ofcorrosion,
pitting and cracks. Replace as necessary.
10. Inspect all air line fittings for corrosion and replace as
necessary. Makecertaintoremovealloldthreadsealant
beforereuse.
ASSEMBLY
1. Priortoassembly,lubricateallo-rings,seals,andpistons,
aswellasbodyandcover bores,usingsiliconelubricant.
2. Installthe largeand smalldiametero-rings(38,39&40)
on the primary inlet seat (37), then insert the small
diameter of the seat (37) into the bore in the cover (3).
Do not cut or pinch the o-rings.

11
3. Install the spring (36) on the inlet seat (37) so that the
small diameter fits over and around the air passage
through the center of the inlet seat.
4. Installo-ring(33) onthe checkvalveseat (32).
5. Using a small amount of grease applied to the check
valve (34) and guide (35) to secure both items to the
check valve seat (32). Gently insert the assembled
items into the valve cover (3). Install the valve guide
(35) so that its flange contains (surrounds) the coils of
the large end of the spring (36), when the valve seat
(32) is installed in the cover (3). Make certain that the
guide (35) is centered over the spring (36), which was
installed in step 3. Note; The check valve must be
installed so that the top hat portion fits into the valve
seat (32).
6. Installthe smallandlarge diametero-rings (27& 28)on
thecheckvalve seat(23).
7. 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.
8. 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 grease to hold these
parts in the valve seat (23).
9. 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.
10.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).
11. Install the inlet and exhaust valve return spring (9) in
the body (4).
12.Install the large and small diameter o-rings (7 & 8) in
the exhaust cover (6), then install the exhaust cover in
thebody (4)takingcarenotto damagetheo-rings. Hold
theexhaustcover in place.
13. 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.
14. Ifthevalvewasequippedwitharelaypiston returnspring
(20), install the spring in the body, large diameter first.
15. Using lubricant to hold them in place, install the large
and small sealing rings (18 & 17) on the cover (3).
16. Installtheo-ring(21)onthe relaypiston(19), theninstall
the piston in the body (4).
17. Notethe relationshipmarks madeprior todisassembly,
then install the cover (3) on the body (4). Secure the
coveronthe bodyusing thetwo,short capscrews (16).
Again,noting therelationshipmarks,securethebracket
(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.
18. Install the two cap screws (14) that secure the bracket
(15) to the cover (3) and torque to 180 - 220 pound
inches.
19.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.
20.Install allair linefittings andplugs makingcertainthread
sealing material does not enter the valve.
Install the rebuilt valve on the vehicle and perform the
OPERATION AND LEAKAGE TESTS before placing the
vehicle in service.
Key DescriptionQty. I.D. O.D. W
7 O-Ring 1 1.424 1.630 0.103
8 O-Ring 1 0.862 1.068 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 0.070
30 O-Ring 1 1.356 1.496 0.070
31 O-Ring 1 1.176 1.316 0.070
33 O-Ring 1 1.176 1.316 0.070
38 O-Ring 1 1.176 1.316 0.070
39 O-Ring 1 0.801 0.941 0.070
40 O-Ring 1 0.739 0.879 0.070
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O-RING IDENTIFICATION

12 BW1969 © 2004 Bendix Commercial Vehicle Systems LLC. All rights reserved. 9/2004 Printed in U.S.A.