BENDIX PP-3 TRAILER SUPPLY VALVE User manual

1
®
Bendix®PP-3™Trailer Supply Valve
SD-03-3613
FIGURE 2
MOUNTING
NUT
PP-3™
CONTROL
VALVE
DELIVERY
PORT
NO.2
RESERVOIR
TC-2™VALVE
FIGURE1 -PP-3™TRAILER SUPPLYVALVEEXTERIOR
SUPPLY
PORT
BUTTON
TP-3™
TRACTOR
PROTECTION
VALVE
DOUBLE
CHECK
VALVE
COMPRESSOR
TRAILERSERVICE
LINE
TRAILER
EMERGENCYLINE
BRAKE
VALVE
NO.1
RESERVOIR
DESCRIPTION
ThePP-3™trailer supplyvalve,installedinthecab,operates
inconjunction withaTP-3™tractor protectionvalveto supply
air under pressure to the trailer and protect the tractor air
supply in case of a break-away or an air leak on the trailer
which would reduce the pressure in the trailer supply line
belowthedesign trip point of the PP-3™valve.
With reference to Figure 2 the supply port of the PP-3™
valve is supplied from the towing vehicle reservoir. Its
deliverygoesdirectly to thesupplyporton the TP-3™tractor
protectionvalve.
OPERATION
ThePP-3™controlvalveis a push-pull operated valve. The
buttonmustbepushedin to open the valve. The button will
not stay in unless there is 50 psi or more in the supply line.
Once the pressure is enough that the button will remain in,
airflowsthroughthetractor protection valve to the trailer.

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If,inthe case ofanemergencyorfor some other reasonthe
driver wishes an application of the trailer brakes, he pulls
thePP-3™valve controlbuttonout.Emergencyline pressure
will exhaust out the PP-3™valve exhaust port causing an
application of the trailer brakes.Also, theTP-3™inlet valve
seatsandcloses the serviceline.ThePP-3™valvebutton is
pulledoutandleftoutduringbob-tailedoperationofthetractor.
In normal use the button is pulled out before uncoupling
fromthe trailer and pushed inaftercouplingto the trailer.
Shoulda condition occurresultinginair loss fromthetractor
or trailer system through leakage and the driver fails to
manually pull out the PP-3™valve button, the PP-3™valve
will automatically close at approximately 40 psi and seal
the tractor air lines. The driver cannot, in this condition,
overcomethe emergencyapplicationofthe trailerbrakesby
holding the PP-3™valve button in. If the driver should hold
thebuttonin as emergency line pressure bleeds downfrom
the 40 psi range to approximately 30 psi, the tripper piston
will move and open the tripper exhaust in the PP-3™valve.
Emergencylineairwillexhaustthroughthetripper exhaust
andholdthetrailer brakes applied.
PREVENTIVE MAINTENANCE
Important: Review the Bendix Warranty Policy before
performinganyintrusivemaintenanceprocedures.Awarranty
maybevoided if intrusive maintenance is performedduring
thewarrantyperiod.
No two vehicles operate under identical conditions, as a
result, maintenance intervals may vary. Experience is a
valuableguide in determiningthebestmaintenance interval
forairbrakesystemcomponents.Ata minimum, the PP-3™
valveshouldbeinspectedevery12monthsor3600operating
hours,whichever comes first, for properoperation. Should
the PP-3™valve not meet the elements of the operational
testsnotedinthisdocument,furtherinvestigationandservice
ofthevalve may be required.
OPERATING AND LEAKAGE CHECKS
To make the following operating and leakage checks, an
accurate test gauge installed in a spare hose coupling is
required. The vehicle dash gauge should be checked for
accuracyagainstthe test gaugepriortomaking these tests.
1. Block and/or hold the vehicle by ameansother than air
brakesduringthese tests.
2. Drain vehicle reservoir supply, then close drain cocks.
3. Connect assembled hose coupling and test gauge in
tractoremergency hosecoupling.Startengine andbuild
up system pressure.
4. As reservoir pressure builds up there should be no
pressurereading on testgauge.Whensystempressure
reaches the 30 to 40 psi range on dash gauge make
and hold a foot or hand valve application and observe
that no air escapes at the open trailer service hose
coupling.
5. When system pressure reaches approximately 60 psi,
the PP-3™valve button should be pushed in. System
pressure should show at once on the test gauge
connected in the emergency line and the button of the
PP-3™valveshouldremaininwithoutbeingheld.
6. Buildsystempressure uptoapproximately100 psi,then
stop engine. With engine stopped, wait momentarily,
then notice that dash gauge and test gauge pressure
readingequal.While still in this position, make a footor
handvalveapplicationandobservethat air is delivered
outtheopentrailerservicecoupling.
7. With PP-3™valve button still in, check for leakage at
PP-3™valveexhaust andtripperexhaust ports.Leakage
should not exceed a 1" bubble in 5 seconds at either
point.
8. WithPP-3™valvebutton still in, check for leakageatthe
TP-3™valveexhaustandopenservicecoupling.Leakage
should not be more than a 1" bubble in 5 seconds at
eitherpoint.
9. Pull the PP-3™valve button out: pressure on the test
gauge connected in the emergency line should drop to
zero.Makeandholdahandvalveapplicationandobserve
thatair delivered at the open service coupling does not
exceed a 1" bubble in 5 seconds. Release foot or hand
valveapplication.
NOTE:If thePP-3™valvedoes notfunctionasdescribed
or if leakage is excessive, it is recommended that it be
returnedtothe nearest Bendix authorized distributor for
a factory rebuilt valve. If this is not possible, the valve
shouldbe repaired usinggenuineBendixparts, inwhich
casethefollowing should prove helpful.
REMOVING AND INSTALLING
REMOVING
1. Blockand/orhold the vehicle by a means otherthanair
brakes. Drain air brake system.
2. DisconnectsupplyanddeliverylinesfromPP-3™valve.
3. DriveoutPP-3™valve buttonrollpinand remove button.
RemovePP-3™valve mounting nut,thenPP-3™valve.
INSTALLING
Wheninstallingthe PP-3™valve, refer to Figure2forproper
connectionsalongwithfollowingexplanations:
1. Supplylinefrom tractor reservoir is connectedtosupply
portof PP-3™valve.
2. DeliverylinefromPP-3™valvedeliveryport isconnected
totractoremergencyportofTP-3™valve.
3. PP-3™valve exhaust port and tripper exhaust must be
open.
4. Two(2)portsmarked“Del” onupperPP-3™controlvalve
bodyarepluggedandmustremainplugged.

3
DISASSEMBLY
PP-3™PUSH-PULLVALVE
1. Buttonpin(1) Figure 3, button(2) and mounting nut(3)
are normally removed when valve is removed from
vehicle.
2. Removetwolowerbodycapscrews(4)andlockwashers,
thenlowerbody(5)withcover(6).
3. Remove cover with tripper piston (7) from lower body.
4. Remove tripper piston and spring (8) from cover.
5. Removetripperpistonandcoversealo-rings(9&10).
6. Insert rod or punch in upper plunger pin hole and hold
plunger (11) from turning while inlet and exhaust valve
nutisremoved.
7. Removewasher(13)andvalve(14).
8. Pullplungerfromupperbody.
9. Removeplungerspring (15)ando-ring(16).
10. Removeupperbodyseal ring(17).Donot removeplugs
from ports marked “Del” in upper body.
CLEANINGANDINSPECTION OF PARTS
Wash all metal parts in mineral spirits and then dry.
In particular, make sure supply port in PP-3™valve upper
body,tripper by-passslot, and tripper exhaust port in cover
arethoroughlycleanedandunrestricted.
Inspectallpartsforexcessivewear or deterioration.
Inspect seats in upper and lower body for nicks and burrs.
Redressseatsifdamaged.
Inspectplunger andtripperpistonbores inbodiesandcover
for deep scratches or nicks. They should be smooth and
clean.
Check springs for distortion, corrosion, and cracks.
Replace all parts not considered serviceable during these
inspections,especiallyo-ringsandvalves.
ASSEMBLY
Prior to assembly, lubricate o-rings and bearing surfaces
with silicone lubricant Bendix Pc. No. 291126.
1. Installplungero-ring (16).
2. Position plunger spring (15) in upper body, then press
plunger (11) down inside spring in the body.
3. Place inlet and exhaust valve (14), then washer (13),
over threaded, protruding end of plunger.
4. Install and tighten self-locking nut (12). Torque on the
nut should be 30 to 40 inch pounds.
5. Placeupperandlower body seal o-ring (17) in place.
6. Installtripperpistono-ring(9).
7. Positioncovero-ringseal (10) on cover.
8. Position tripper spring (8) in cover (6) then press tripper
piston (7) down over spring and into the cover bore.
9. Place cover with tripper installed into lower body.
10.Fasten lower body and cover assembly to upper
assemblywithcap screws (4)andlockwashers.Tighten
cap screws evenly and securely.
TESTING REBUILT PP-3™VALVE
Performoperatingandleakagechecksasoutlinedinprevious
section.
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.
FIGURE 3 - PP-3™CONTROLVALVE
SPIROL PIN (1)
EXHAUST
PORT
PLUNGER (11)
TRIPPER
SPRING(8)
BUTTON (2)
SUPPLY
PORT
INLET AND
EXHAUST
VALVE(14)
SPRING(15) NUT (3)
O-RING (16)
PIPEPLUG
SEAL(17)
INLET AND
EXHAUST
VALVENUT
(12)
LOWERBODY
(5)
O-RING (9)
CAPSCREW
(4)
TRIPPER
EXHAUST
COVER(6)
TRIPPER
PISTON (7)
DELIVERY
PORT
WASHER(13)
O-RING (10)

4BW1437 © 2004 Bendix Commercial Vehicle Systems LLC. All rights reserved. 3/2004 Printed in U.S.A.
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 andobserve
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
recommendedprocedures, deactivate theelectrical
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.