BENDIX BP-R1 BOBTAIL PROP RELAY VALVE Manual

BENDIX BP-R1 BOBTAIL PROP RELAY VALVE Manual

Bobtail proportioning relay valve

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®
Bendix
BP-R1
CONTROL
EXHAUST
SUPPLY

DESCRIPTION

The BP-R1
bobtail proportioning relay valve is a combina-
tion of two individual valves in a single housing. The lower
portion, or body, of the BP-R1
service brake relay valve, which functions as a relay station
to speed up brake application and release. The upper por-
tion, or cover, houses a brake proportioning valve, which
reduces normal service brake application pressure when
the tractor is not towing a trailer.
Used in tractor air brake systems only, the BP-R1
is installed in place of a standard relay valve. It functions
as a standard service relay during operation of a tractor-
trailer combination. During bobtail tractor operation, the
BP-R1
valve improves controllability and reduces stopping
distances by reducing air pressure to the rear actuators/
chambers, whose axle load has been greatly reduced.
While the BP-R1
valve can incorporate various crack
pressures to accommodate specific applications, the
standard is 4 psi.
Bobtail Proportioning Relay Valve
SERVICE
DELIVERY
valve contains a "standard"
FIGURE 1 - BP-R1
Designed for frame or cross member mounting, the BP-R1
valve is furnished with a mounting bracket which is attached
to two of the four cover cap screws. Replacement valves
are furnished with a universal mounting bracket, which
allows the BP-R1
relays.
All air connections on the BP-R1
cast, embossed letters for ease of installation. The letter
valve
identifi cation and air line connections are shown below
for reference.
BP-R1
Valve Air Connection
Supply (to reservoir)
Delivery (to brake actuator)
Service (brake valve rear axle service delivery)
Control (to delivery of trailer supply valve)
SERVICE
CONTROL
BOBTAIL PROPORTIONING RELAY VALVE
valve to replace most standard
valve are identifi ed with
Embossed Identifi cation
EXHAUST
SUPPLY
SUP
DEL
SER
CON
1

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Table of Contents
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Summary of Contents for BENDIX BP-R1 BOBTAIL PROP RELAY VALVE

  • Page 1 ® ™ Bendix BP-R1 Bobtail Proportioning Relay Valve SERVICE CONTROL SERVICE CONTROL EXHAUST EXHAUST SUPPLY DELIVERY SUPPLY ™ FIGURE 1 - BP-R1 BOBTAIL PROPORTIONING RELAY VALVE DESCRIPTION The BP-R1 ™ bobtail proportioning relay valve is a combina- Designed for frame or cross member mounting, the BP-R1 ™...
  • Page 2 “BLEND BACK” CONTROL TRAILER TRACTOR SERVICE PISTON PORT SUPPLY PROTECTION PORT SERVICE PROPORTIONING PISTON PISTON EARLIER INLET-EXHAUST MODELS HAVE SERVICE PORT VALVE A DIAPHRAGM HERE BP-R1 ™ VALVE SPRING DELIVERY CONTROL RELAY PORT(4) PORT PISTON DUAL SUPPLY SPRING BRAKE (NOT USED VALVE SERVICE IN ALL...
  • Page 3 SERVICE BRAKES HOLDING — TRACTOR/ TRAILER COMBINATION The air pressure being delivered to the brake actuators is PROP also present beneath the relay piston. PISTON When the air pressure above and below relay piston is equal, the piston moves slightly allowing the inlet valve to INLET-EXHAUST VALVE return to its seat.
  • Page 4 Service applications of more than 80 psi cause the blend back piston to begin to move. Service air pressure acting on the full diameter of the blend back piston overcomes the PROP resistance of reservoir pressure acting on the large diam- PISTON eter of the other side.
  • Page 5 Never remove described or leakage is excessive, it should be repaired a component or plug unless you are certain all or replaced with a new or genuine Bendix remanufactured system pressure has been depleted. ®...
  • Page 6 Note: Early models used a Diaphragm(19), Dust Shield(16) Service Piston(17), o-ring(21) ........... 1 BODY SERVICE PISTON ORIGINAL STYLE ......... 2 21) ....... 20 VALVE COVER QUIRED O RING ......3 RETAINING RING SERVICE PISTON NEW STYLE DOES NOT ......4 ) ......
  • Page 7 ™ 6. Check the BP-R1 valve differential pressure by apply- 2. Drain the air pressure from all vehicle reservoirs. ing 10 psi to the service port and noting the pressure 3. Identify and mark or label all air lines and their registered at the delivery port.
  • Page 8 Figure 11), seals, and pistons as well as body and cover the valve cover (2), then remove and discard both bores, using the lubricant provided with the Bendix o-rings (27 & 29). maintenance kit. Use all of the lubricant and spread it 16.
  • Page 9 3. Install the small end of the inlet/exhaust valve spring 14. Install the retaining ring (15), making certain it is fully (34) over the rubber of the valve (33), making sure the seated in its groove. spring coils rest on the valve’s four tabs. Note: Both 15.
  • Page 10 BW1624 © 2007 Bendix Commercial Vehicle Systems LLC. All rights reserved. 7/2007 Printed in U.S.A.

Table of Contents