BENDIX RV-4 PRESSURE REDUCING VALVE Operating and maintenance instructions

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®
Bendix®RV-4™Pressure Reducing Valve
SD-03-3520
FIGURE 1
GENERAL DESCRIPTION
The RV-4™pressure reducing valve is a normally open
pressurecontroldevice.ThefunctionoftheRV-4™valveis
to reduce system air pressure and maintain a constant
specified pre-set pressure below that of system pressure.
Variouspressuresettingscanbe obtainedthroughtheuse
of springs and shims in combination.
TheRV-4™valvehasonesupply portandtwo deliveryports.
Asinglepipeplugisinstalledin the control port and should
remaininplace.
OPERATION
Thespringforceexertedonthebalancepistondetermines
the delivery pressure of the valve. With no air pressure
present at the supply port, the inlet valve is unseated and
open while the exhaust passage through the center of the
controlpistonissealedbythe exhaust valve. Compressed
air entering the supply port flows past the open inlet valve,
around the balance piston and out the two delivery ports.
Whenairpressureon the balance pistonovercomesspring
force,thepistonmoves and thevalvespringforcesthe inlet
valve on its seat, closing off the supply of air. The exhaust
remains closed. If air pressure in the delivery line drops,
spring force under the balance piston overcomes air
pressure.Subsequentpistonmovementwillunseat theinlet
valveallowingadditional air pressure intothedeliverylines.
Ifpressureinthedeliverylines exceedsthepressuresetting
of the valve, the force exerted by the air pressure will be
greaterthanthespringforce.Thebalancepistonwillmove
awayfromtheexhaustvalve,permittingairtoflowpastthe
exhaust valve, through the hollow piston stem and out the
exhaustport.Theinletvalvewillremainclosed.
MOUNTING
HOLE (2)
EXHAUST
CONTROL
PORT
(PLUGGED)
DELIVERY(2)
SUPPLY
PORT
BALANCE
PISTON
SPRINGS
DELIVERY
PORT (2)
SUPPLY
PORT
BALANCE
PISTON
CONTROL
PISTON
CONTROL
PORT
(PLUGGED)
EXHAUST
SPRING
SHIMS
EXHAUSTPASSAGE
VALVE
SPRING

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PREVENTIVE MAINTENANCE
Important: Review the Bendix Warranty Policy before
performinganyintrusivemaintenanceprocedures.Awarranty
maybevoidedif intrusive maintenanceisperformedduring
thewarrantyperiod.
No two vehicles operate under identical conditions, as a
result, maintenance intervals may vary. Experience is a
valuableguidein determiningthebestmaintenance interval
forairbrakesystemcomponents.At a minimum, theRV-4™
valveshould beinspectedevery6months or1500operating
hours,whichevercomes first, for proper operation. Should
the RV-4™valve not meet the elements of the operational
testsnotedinthisdocument,furtherinvestigationandservice
ofthevalve may berequired.
OPERATING & LEAKAGE TESTS
OPERATING
Connect an accurate test gauge in the supply and delivery
lines of the RV-4™valve. Make certain that supply air
pressureisatthevehiclemanufacturersrecommendedlevel.
Delivery pressure should be within plus or minus 5 p.s.i. of
the delivery pressure specified for the RV-4™valve. If not,
thevalveshouldbe repaired or replaced. Ifthevalvemeets
this operating test, proceed to the leakage tests. Do not
remove the gauges at this time.
LEAKAGE
Withsupplypressureatthelevelrecommendedbythevehicle
manufacturer, apply a soap solution to the 1/4" N.P.T. plug
inthe controlport,aroundthesupplyportandtotheexhaust.
Leakage should not exceed a 1" diameter bubble in 3
seconds (175 SCCM). If leakage is excessive, the valve
shouldberepairedorreplacedandtheoperatingandleakage
testsperformedatthetimeofrepairorreplacement.Proceed
tothe“RemovalandInstallation”instructions.Thisconcludes
theoperationandleakage tests andthetestgaugesshould
beremoved.
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 in operation,EXTREMECAUTION 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. Useonlythe propertoolsand 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 certainto drainthe airpressure 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
notattemptrepairs requiring machiningorwelding
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.
REMOVAL & INSTALLATION
REMOVAL
1. Holdthevehicle on a levelsurfacebymeans other than
the air brakes.
2. Removeallair pressure fromallreservoirs.
3. Identify, mark and then disconnect all air lines
attachedtothevalve.
4. Removethevalve.
INSTALLATION
1. Inspectandcleanallairlinesthatconnecttothevalve.
2. Clean the vehicle valve mounting area and mount the
valve.
3. Reconnect the air lines according to the identification
marksmadeduring removal.
DISASSEMBLY (Refer to Figure 2)
1. Removeexhaustcoverscrew(1),exhaustcover(2),and
exhaustdiaphragm(3).
2. Remove four cap screws (4) with lockwashers (5) and
cover(6).
3. Removecontrolpiston(7).

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FIGURE 2
4. Remove large retaining ring from body (8) and remove
inlet/exhaustvalveassembly(9).
5. Removeretainingringfrominlet/exhaustvalveassembly.
Remove o-ring retainer (11), remove inner and outer
o-rings(12&13) from retainer.Removespring (14) and
springseat(15) from valvebody(16).
6. Removefourcapscrews(17)withlockwashers(18)from
oppositeendand removecover(19).
7. Removeshims(20)andinner(21)andouter(22)springs.
8. Remove balance piston (23). Remove o-ring (24) from
balancepiston.
9. Remove retaining ring (25) from supply port. Remove
supply adapter (26). Remove o-ring (27) from supply
adapter.
ASSEMBLY (REFER TO FIGURE 2)
Before assembly, lightly lubricate all o-rings, bores and
matingsurfaceswith (Bendix Pc.No.291126)DowComing
55-Mpneumaticgrease or equivalent.
1. Install o-ring (27) on supply adapter (26), place into
supplyportandinstallretaining ring (25).
2. Install o-ring (24) on balance piston (23), place piston
into body.
3. Install inner (21) and outer (22) springs into base of
balance piston and place shims (20) on top of springs.
4. Replacecover(19) andattachwithfour cap screws(17)
with lockwashers (18). Torque to approximately 45 in.
lbs.
5. Installspringseat (15)andspring (14)ontoinlet/exhaust
valvebody(9).Installo-rings(12&13)ontoo-ringretainer
(11)and placeontopofspring(14),compressand install
retainingring(10).
6. Install inlet/exhaust assembly (9) into valve body and
installretainingring(8).
7. Installcontrolpiston(7) into valve body.
8. Replace cover (6) and attach with four cap screws (4)
and lockwashers (5). Torque to approximately 100 in.
lbs.
9. Installexhaustdiaphragm(3)andexhaustcover(2)on
tovalvecover(6)andattach with screw (1).
TESTING REBUILT RV-4™PRESSURE
REDUCING VALVE
Performoperatingandleakagetestsasoutlined.
KeyNo. Description
1 Screw
2 Cover
3 Exhaust Diaphragm
4 Cap Screw
5 Lock Washer
6 Cover
7 Control Piston
8 Retaining Ring
9 Inlet/ExhaustAssy.
KeyNo. Description
10 Retaining Ring
11 O-Ring Retainer
12 O-Ring
13 O-Ring
14 Spring
15 Spring Seat
16 ValveBody
17 Cap Screws
18 Lockwashers
KeyNo. Description
19 Cover
20 Shims
21 Inner Spring
22 Outer Spring
23 Balance Piston
24 O-Ring
25 Retaining Ring
26 SupplyAdapter
27 O-Ring
12
3
8
9
18
17
19
2021
22 24
23
16
15
14
11
12 & 13
10
5
46
7
SUPPLY PORT
3/8” P.T.
25
26
27
SECTIONVIEW OF SUPPLYPORT

4BW1588 © 2004 Bendix Commercial Vehicle Systems LLC. All rights reserved. 4/2004 Printed in U.S.A.