BENDIX R-12-R-14 RELAY VALVES User manual

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Bendix®R-12™& R-14™Relay Valves
DESCRIPTION
The relay valve in an air brake system functions as a relay
stationtospeeduptheapplicationandreleaseofthebrakes.
The valve is normally mounted at the rear of the vehicle in
proximitytothechambersit serves.Thevalveoperatesas a
remotecontrolledbrakevalve thatdeliversor releases airto
the chambers in response to the control air delivered to it
fromthe foot brake valve or other source.
The R-12™and R-14™relay valves are designed for either
reservoirorframemounting.Auniversalmountingbracketis
furnished that permits easy interchange with other Bendix
relayvalves.Bothvalvesareavailable in thetwobodystyles
illustrated in Figure 1. The R-14™valve differs from the
R-12™valve in that it incorporates a quick release and anti-
compounding feature located above its horizontal service
port. The R-14™valve’s anti-compound feature allows it to
be conveniently used as either a service or spring brake
relay valve. An exhaust cover is installed that protects the
1/8" balance port when the R-14™valve anti-compound
feature is not in use.
FIGURE 1 - EXTERIOR VIEWS
EXTERIOR R-14HEXTERIOR R-12H
SERVICE (1)
SUPPLY (2) DELIVERY
SERVICE (1)
DELIVERY SUPPLY (2)
EXTERIOR R-12V EXTERIOR R-14V
SD-03-1064
DELIVERY
DELIVERY
SUPPLY

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Allpartsare interchangeable betweentheR-12™andR-14™
valves with the exception of the detail components of the
R-14™valvecover.Bothvalves makeextensive useofnon-
metallicinternalcomponents.Foreaseofservicing,theinlet/
exhaust valve can be replaced without the need for line
removal.
OPERATION
APPLICATION
Air pressure delivered to the service port enters the small
cavity above the piston and moves the piston down. The
exhaust seat moves down with the piston and seats on the
inner or exhaust portion of the inlet/exhaust valve, sealing
offtheexhaustpassage.Atthe sametime, the outeror inlet
portionoftheinlet/exhaustvalvemovesoffitsseat,permitting
supplyairtoflowfromthe reservoir,pasttheopeninletvalve
and into the brake chambers.
BALANCE
Theairpressurebeing delivered bytheopeninlet valve also
is effective on the bottom area of the relay piston. When air
pressurebeneaththe pistonequalsthe serviceairpressure
above, the piston lifts slightly and the inlet spring returns
the inlet valve to its seat. The exhaust remains closed as
theserviceline pressure balancesthe delivery pressure.As
deliveredairpressure ischanged, thevalvereacts instantly
to the change, holding the brake application at that level.
EXHAUST OR RELEASE
When air pressure is released from the service port and air
pressure in the cavity above the relay piston is exhausted,
airpressure beneaththe pistonlifts therelay pistonand the
exhaust seat moves away from the exhaust valve, opening
the exhaust passage. With the exhaust passage open, the
air pressure in the brake chambers is then permitted to
exhaust through the exhaust port, releasing the brakes.
ANTI-COMPOUNDING (SIMULTANEOUS
SERVICE AND PARK APPLICATION)
Inthoseapplications wheretheR-14™relayvalveisused to
control spring brake chambers, the anti-compound feature
may be utilized. With the anti-compound feature of the
R-14™valve connected, a service application made while
thevehicleisparkediscounteredbya release oftheparking
brakes.Toutilizethis feature,theexhaust coverofthe quick
release portion of the R-14™valve is removed and a line is
installed which is connected to the delivery of the service
brakevalveorrelayvalve.Withnoairpressureattheservice
port of the R-14™valve, the parking brakes are applied. If a
servicebrakeapplicationismade, air fromtheservicebrake
valve enters the exhaust port of the quick release of the
R-14™valveandmovesthediaphragm, blocking theservice
port.Air then proceedsintothecavityabovethe relay piston,
forces the piston down, closing the exhaust and opening
theinletto deliverairto thespringbrake cavityasdescribed
under the section of this manual entitled Application.
PREVENTIVE MAINTENANCE
Important: Review the Bendix Warranty Policy before
performinganyintrusivemaintenanceprocedures.Awarranty
maybe voided ifintrusive maintenanceis performed during
thewarranty period.
INLET/
EXHAUST
ASSEMBLY
EXHAUST COVER
FIGURE 2 - SECTIONAL VIEWS
RELAY
PISTON
INLET
EXHAUST
VALVE
ASSEMBLY
R-14H
R-12V
RETAINING
RING
EXHAUST
SEAT RELAY
PISTON
EXHAUST
SEAT
RETAINING
RING
EXHAUST
PORT
DIAPHRAGM
BALANCE/QUICK EXHAUST PORT
(ANTI-COMPOUND)
EXHAUST
PORT

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No two vehicles operate under identical conditions, as a
result, maintenance intervals may vary. Experience is a
valuableguidein determining thebestmaintenance interval
for air brake system components.At a minimum, the valve
shouldbeinspectedevery6monthsor1500operatinghours,
whichevercomesfirst,forproperoperation.Shouldthe valve
not meet the elements of the operational tests noted in this
document,furtherinvestigationandserviceof the valve may
berequired.
OPERATIONAL AND LEAKAGE TEST
1. Chock the wheels, fully charge the air brake system
and adjust the brakes.
2. Make several brake applications and check for prompt
application and release at each wheel.
3. Checkforinlet valveand o-ringleakage.
A. Make this check with the service brakes released
whentheR-12™orR-14™valve isusedtocontrol the
servicebrakes.
B. Make the check with the spring brakes applied
(PARK) when the R-14™valve is used to control the
spring brakes. Coat the exhaust port and the area
around the retaining ring with a soap solution; a 1”
bubble in 3 seconds leakage is permitted.
4. Checkforexhaust valveleakage.
A. Makethischeckwith theservicebrakesfully applied
iftheR-12™orR-14™valvecontroltheservicebrakes.
B. Makethischeckwiththespring brakes fullyreleased
iftheR-14™valveisusedtocontrolthespringbrakes.
Coattheexhaustportwithasoapsolution;a1”bubble
in 3 seconds leakage is permitted. Coat the outside
ofthe valvewhere thecover joinsthe body to check
for seal ring leakage; no leakage is permitted.
5. If the R-14™valve is used to control the spring brakes,
place the park control in the released position and coat
the balance port with a soap solution to check the
diaphragmanditsseat.Leakageequivalenttoa1”bubble
in 3 seconds is permitted.
Note: Iftheanti-compoundfeature isinuse,thelineattached
to the balance port must be disconnected to perform this
test.
Ifthevalvesdonotfunctionasdescribedabove,orifleakage
isexcessive,it isrecommendedthat thevalves be replaced
with new or remanufactured units or repaired with genuine
Bendixparts,availableatanyauthorizedBendixpartsoutlet.
REMOVAL AND INSTALLATION
REMOVAL
1. Block and hold vehicle by means other than air brakes.
2. Drain air brake system reservoirs.
3. Ifentirevalveistoberemoved,identifyairlinestofacilitate
installation.
4. Disconnectair lines from valve*.
5. Remove valve from reservoir or if remotely mounted,
removemountingboltsand thenvalve.
*Itisgenerallynotnecessarytoremoveentirevalvetoservice
theinlet/exhaustvalve.Theinlet/exhaustvalveinsert can be
removedbyremoving thesnapring,exhaustcoverassembly
andtheninlet/exhaust valve.
Caution: Drain all reservoirs before attempting to remove
theinlet exhaustvalve.
DISASSEMBLY
Note: Prior to disassembly, mark the location of the
mounting bracket to the cover and the cover to the body.
1. Remove the four (4) cap screws and lockwashers
securing the cover to the body.
2. Removethe cover, sealing ring, and mounting bracket.
3. Removethe piston ando-ring from thebody.
4. Whiledepressingtheexhaustcover,removetheretaining
ring and slowly relax the spring beneath the exhaust
cover.
5. Removethe exhaustcover assemblyand o-rings.
6. Remove the inlet/exhaust valve return spring from the
body.
7. Removethe inlet/exhaust valvefrom thebody.
8. Removethevalve retainer fromtheinlet/exhaust valve.
9. RemovethePhillipshead screw andexhaustcoverfrom
theR-14™valvecover.
10. Remove the service port cap nut and o-ring from the
R-14™valve.
11. Removethediaphragmfromthe R-14™valvecover.
CLEANING AND INSPECTION
1. Wash all metal parts in mineral spirits and dry them
thoroughly.
(Note: When rebuilding, all springs and all rubber parts
shouldbe replaced.)
2. Inspect all metal parts for deterioration and wear, as
evidenced by scratches, scoring and corrosion.
3. Inspect the exhaust valve seat on the relay piston for
nicks and scratches which could cause excessive
leakage.
4. Inspecttheinlet valve seatin the bodyfor scratches and
nicks, which could cause excessive leakage.
5. Inspecttheexhaust seatofthe quick releasediaphragm
in the R-14™valve cover and make sure all internal air
passages in this area are open and clean and free of
nicks and scratches.
6. Replaceallpartsnotconsideredserviceableduringthese
inspections and all springs and rubber parts. Use only
genuine Bendix replacement parts, available from any
authorized Bendix parts outlet.

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QUICK
RELEASE
VALVE
PP-7
™
VALVE
DS-2
™
DOUBLE
CHECK &
STOP LIGHT
TP-3
™
TRACTOR
PROTECTION
DC-4
™
DOUBLE
CHECK
VALVE
BRAKE
CHAMBER
AIR DRYER
SUPPLY
RESERVOIR
ANTI-COMPOUND
LINE
BP-R1
™
BOBTAIL
PROPORTIONING
VALVE
FRONT AXLE
SERVICE
RESERVOIR
REAR AXLE
SERVICE
RESERVOIR SPRING
BRAKES
GAUGE
SR-5
™
TRAILER
SPRING
BRAKE VALVE
SUPPLY LINE
SERVICE LINE
E-7
™
,
E-12
™
OR
E-15
™
VALVE
R-14
™
RELAY
VALVE
R-12
™
RELAY
VALVE
SPRING
BRAKES
COMPRESSOR
MV-3
™
MODULE
TRAILER
RELEASE
TRAILER
PARK
SYSTEM
PARK
LP-3
™
INDICATOR
TRAILER
CONTROL
VALVE
PP-1
™
VALVE
PP-1
LQ-5
™
VALVE
FIGURE 3 - TYPICAL PIPING SCHEMATIC
SR-1
™
SPRING
BRAKE VALVE
FRONT
SERVICE
RESERVOIR
REAR
SERVICE
RESERVOIR

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ASSEMBLY
Note:Alltorquespecifiedinthismanualareassemblytorque
and can be expected to fall off slightly after assembly. Do
notre-torqueafterinitialassemblytorquefall.Forassembly,
handwrenchesare recommended.
Priortoassembly, lubricateall o-rings, o-ringbores andany
sliding surface with a silicone lubricant equivalent to Dow
Corning#10.
1. Install large piston o-ring on piston.
2. Install inner and outer o-rings in the exhaust cover
assembly.
3. Install the sealing ring on the cover.
4. Install piston in body, taking care not to damage the
pistono-ring.
5. Noting the reference marks made during disassembly,
install the cover on the valve body and the mounting
bracketon the cover.
6. Securethemountingbracketandcovertothebodyusing
thefour (4)cap screwsand lockwashers.Torque to80-
120 inch pounds.
7. Install the valve retainer on the inlet/exhaust valve and
install in the body.
8. Install the inlet/exhaust valve return spring in the body.
9. Install the exhaust cover assembly in the body, taking
care not to damage the o-ring.
10. Whiledepressing theexhaust cover, installthe retaining
ring. Make certain the retainer is completely seated in
its groove in the body.
11. InstalltheR-14™valve serviceport cap nuto-ring onthe
cap nut.
12. Install the diaphragm in the R-14™valve cover making
certain it is positioned between the guide ribs in the
cover.
13. Install the service port cap nut and torque to 150 inch
pounds.
14. If the quick release exhaust port was protected with an
exhaustcover, installthecoverusingthe #10-24Phillips
head screw. Torque to approx. 15-25 inch pounds.
15. TestthevalvesasoutlinedintheOperationalandLeakage
Test section before returning the valve to service.
INSTALLATION
1. Clean air lines.
2. Inspect all lines and/or hoses for damage and replace
as necessary.
3. Installvalve and tighten mounting bolts.
4. Connect air lines to valve (plug any unused ports).
5. TestvalveasoutlinedinOperationaland Leakage Tests.
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
engine bein 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. Useonly 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,makecertaintodraintheairpressurefrom
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,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.

6BW1431 © 2004 Bendix Commercial Vehicle Systems LLC. All rights reserved. 3/2004 Printed in U.S.A.