Bendix® BP-R1™ Bobtail Proportioning Relay Valve
SD-03-1067
CONTROL
EXHAUST
SUPPLY
DELIVERY
DESCRIPTION
The BP-R1™ bobtail proportioning relay valve is a combination of two individual valves in a single housing. The lower
portion, or body , of the BP-R1™ valve contains a “standard”
service brake relay valve, which functions as a relay station
to speed up brake application and release. The upper portion, 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™ valve
is installed in place of a standard relay valve. It functions
as a standard service relay during operation of a tractortrailer combination. During bobtail tractor operation, the
™
BP-R1
distances by reducing air pressure to the rear actuators/
chambers, whose axle load has been greatly reduced.
While the BP-R1
pressures to accommodate specific applications, the
standard is 4 psi.
valve improves controllability and reduces stopping
™
valve can incorporate various crack
SERVICESERVICE
FIGURE 1 - BP-R1™ BOBTAIL PROPORTIONING RELAY VALVE
CONTROL
EXHAUST
SUPPLY
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™ valve to replace most standard
relays.
™
All air connections on the BP-R1
valve are identifi ed with
cast, embossed letters for ease of installation. The letter
identifi cation and air line connections are shown below
for reference.
BP-R1
™
Valve Embossed
Air Connection Identifi cation
Supply (to reservoir) SUP
Delivery (to brake actuator) DEL
Service (brake valve rear axle service delivery) SER
Control (to delivery of trailer supply valve) CON
™
1
TRAILER
SUPPLY
TRACTOR
PROTECTION
CONTROL
PORT
“BLEND
BACK”
PISTON
SERVICE
PORT
SERVICE PORT
™
BP-R1
VALVE
CONTROL
PORT
DUAL
BRAKE
VALVE
REAR AXLE
SERVICE RESERVOIR
FIGURE 2 - BP-R1™ TRACTOR AIR SYSTEM
SUPPLY
DELIVERY
PORT(4)
SERVICE
SPRING
BRAKE
OPERATION
INITIAL CHARGING
During the initial build up of tractor system air pressure,
supply air fl ows through internal body and cover passages
in the BP-R1™ valve to the blend back piston.
PROPORTIONING
PISTON
INLET-EXHAUST
VALVE
SPRING
(NOT USED
IN ALL
MODELS)
SUPPLY
PORT
INLET-EXHAUST
VALVE
FIGURE 3 - BP-R1™ BOBTAIL PROPORTIONING RELAY
VALVE
SERVICE
PISTON
EARLIER
MODELS
HAVE A
DIAPHRAGM
HERE
SPRING
RELAY
PISTON
DELIVERY
PORT
of the inlet and exhaust valve. With the exhaust passage
sealed, continued movement of the piston unseats the inlet
portion of the inlet and exhaust valve, allowing supply air
from the reservoir to fl ow out the BP-R1™ valve delivery
ports to the brake actuators. (See Figure 4.)
Activating the trailer supply valve (dash control with red
octagonal button), simultaneously charges the trailer and
the BP-R1™ valve control port. Air entering the BP-R1
™
valve control port causes the proportioning piston to move
toward its stop in the cover. The integral inlet and exhaust
valve is carried along with the piston until it seats and
seals the exhaust passage. Continued movement of the
proportioning piston opens the inlet valve. With the tractor
and trailer air system fully charged, the vehicle may be
operated.
SERVICE BRAKES APPLYING — TRACTOR/
TRAILER COMBINATION
Brake application air enters the BP-R1™ valve service port
and is conducted through the service piston to the exhaust
diaphragm which fl exes in response to the incoming air and
seals the exhaust passage in the exhaust piston. Air fl ows
around the exhaust diaphragm then through the center of
both the blend back and proportioning pistons to the inlet
and exhaust valve. Flowing around the inlet valve, application air moves through a passage in the cover to the top of
the service relay piston. In response to air pressure, the
relay piston moves into contact with the exhaust portion
INLET-
EXHAUST
VALVE
FIGURE 4 - BP-R1
COMBINATION
PROP
PISTON
INLET-EXHAUST
PISTON
™
APPLYING - TRACTOR/TRAILER
RELAY
PISTON
2
SERVICE BRAKES HOLDING — TRACTOR/
TRAILER COMBINATION
The air pressure being delivered to the brake actuators is
also present beneath the relay piston.
When the air pressure above and below relay piston is
equal, the piston moves slightly allowing the inlet valve to
return to its seat. The exhaust valve remains closed. With
both the inlet and exhaust valves closed, air pressure in
the brake actuators is held stable and neither increases
nor decreases. (See Figure 5.)
PROP
PISTON
INLET-
EXHAUST
VALVE
RELAY
PISTON
PROP
PISTON
INLET-
EXHAUST
VALVE
RELAY
PISTON
INLET-EXHAUST
PISTON
FIGURE 6 - BP-R1™ RELEASING - TRACTOR/TRAILER
COMBINATION
INLET-EXHAUST
PISTON
FIGURE 5 - BP-R1™ HOLDING - TRACTOR/TRAILER
COMBINATION
SERVICE BRAKES RELEASING — TRACTOR/
TRAILER COMBINATION
When the brake application is released, air pressure in the
service port of the BP-R1™ valve returns to the foot brake
valve and is exhausted. Air from above the relay piston fl ows
back through the proportioning, blend back and service
pistons to the exhaust diaphragm. If the service brakes are
rapidly released, the diaphragm fl exes in response to the
returning air and opens the exhaust.
If the brakes are slowly released, service air pressure will
fl ow through the slot behind the diaphragm and back to
the brake valve. As air pressure is reduced above the relay
piston, pressure beneath it lifts the piston away from the
exhaust valve and opens the exhaust passage. Air from
the service brake actuators returns to the BP-R1™ valve
and fl ows out the open exhaust. (See Figure 6.)
SERVICE APPLICATION BOBTAIL TRACTOR
When the trailer supply valve (dash control with red octagonal button) is activated to disconnect the trailer, air in the
BP-R1™ valve control port and trailer supply line is exhausted to atmosphere. During bobtail tractor operation, service
application air enters the BP-R1™ valve service port
causing the exhaust diaphragm to seal the exhaust port.
Service application air passing through the blend back
piston exerts a force on the full effective diameter of
the piston. The blend back piston remains stationary at
application pressures below approximately 80 psi because
of opposing reservoir air acting on the large diameter.
Application air fl owing through the blend back piston also
exerts a force on the small diameter of the proportioning
piston while simultaneously fl owing through the center of
it on its way to the inlet and exhaust valve. Once past the
inlet and exhaust valve, service air pressure exerts a force
on the larger diameter end of the proportioning piston,
which opposes the air pressure and spring force exerted
on the other end. The proportioning piston inlet valve
remains open until a preset, initial application pressure
has reached the relay piston assuring that the foundation brake shoes are brought into contact with the drum.
As service pressure begins to exceed the preset initial
application, the proportioning piston will move suffi ciently
to close its inlet valve without opening the exhaust.
3
INLET-
EXHAUST
VALVE
PROP
PISTON
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
resistance of reservoir pressure acting on the large diameter of the other side. Above 80 psi the dif ference between
control and delivered air pressure is reduced and “blends
back” from a proportioned delivery to a full 1:1 delivery.
Complete “blend back” to a 1:1 delivery is achieved when
a full brake application is made, and it will occur regardless
of reservoir pressure level.
RELAY
PISTON
INLET-EXHAUST
PISTON
FIGURE 7 - BP-R1™ HOLDING - BOBTAIL TRACTOR
As service air pressure continues to increase, the inlet valve
opens as necessary to deliver additional but reduced air
pressure to the relay piston, thus to the rear axle brakes.
Proportioning occurs due to the difference in effective area
on each end of the proportioning piston.
TRACTOR/
TRAILER
COMBINATION
SERVICE BRAKES RELEASING — BOBTAIL
TRACTOR
When the brake application is released, air pressure in the
service port of the BP-R1™ valve returns to the foot brake
valve and is exhausted. Air between the closed proportioning piston inlet valve and the service piston returns to the
exhaust diaphragm. If the release is rapid, the diaphragm
fl exes in response to the returning air and opens the
exhaust.
Air from above the relay piston, fl ows back to the pro-
portioning piston causing it to move. As it moves, the
proportioning piston unseats the exhaust valve allowing
air from above the relay piston to escape to atmosphere.
Reducing the air pressure above the relay piston causes
pressure beneath it to lift the piston away from the exhaust
valve. Air from the service brake actuators returns to the
BP-R1™ valve and fl ows out the open exhaust.
PROP
PISTON
INLET-
EXHAUST
VALVE
PRESSURE
VALVE DELIVERY PORT)
™
SERVICE BRAKE CHAMBER
(BP-R1
0 PSI
0 PSI
FIGURE 8 - BP-R1™ CONTROL VS. DELIVERY PRESSURE
4
BRAKE VALVE DELIVERY
PRESSURE
™
(BP-R1
VALVE CONTROL PORT)
BOBTAIL
TRACTOR
RELAY
PISTON
INLET-EXHAUST
PISTON
FIGURE 9 - BP-R1™ RELEASING - BOBTAIL TRACTOR
PREVENTIVE MAINTENANCE
GENERAL
Important: Review the Bendix Warranty Policy before
performing any intrusive maintenance procedures. A warranty may be voided if intrusive maintenance is performed
during the warranty period.
No two vehicles operate under identical conditions, as a
result, maintenance intervals may vary. Experience is a
valuable guide in determining the best maintenance interval
for air brake system components. At a minimum, the valve
should be inspected every 6 months or 1500 operating
hours, whichever comes fi rst, for proper operation. Should
the valve not meet the elements of the operational tests
noted in this document, further investigation and service
of the valve may be required.
Perform the tests and inspections presented at the prescribed intervals. If the BP-R1
described or leakage is excessive, it should be repaired
or replaced with a new or genuine Bendix remanufactured
unit, available at any authorized parts outlet.
Every 3 months, or 25,000 miles or 900 operating
hours:
1. Remove any accumulated contaminates and visually
inspect the exterior for excessive corrosion and physical
damage.
2. Inspect all air lines connected to the BP-R1™ valve
for signs of wear or physical damage. Replace as
necessary.
3. Test air line fi ttings for excessive leakage and tighten
or replace as necessary.
4. Perform the Leakage Test described in this manual.
Every year, 100,000 miles, or 3,600 operating hours:
1. Perform the Operation and Leakage Tests described
in this manual.
™
valve fails to function as
WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO A VOID PERSONAL
INJURY OR 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 be in 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. Use only 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, make certain to drain the air pressure
from all reservoirs before beginning ANY work
on the vehicle. If the vehicle is equipped with an
®
AD-IS
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, fi ttings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifi cally 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 specifi cally 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
lamp should be ON) prior to performing any vehicle
maintenance where one or more wheels on a drive
axle are lifted off the ground and moving.
air dryer system or a dryer reservoir module,
OPERATION & LEAKAGE TESTS
OPERATING TEST
To properly test the function of the BP-R1™ valve, a pair of
test gauges or gauges of known accuracy must be used.
1. Park the vehicle on a level surface and block the wheels
and/or hold the vehicle by means other than the air
brakes.
2. Drain air pressure from all vehicle reservoirs.
3. Install a “tee” at the BP-R1™ valve service port and
at one of the delivery ports, then install a gauge in
each.
5
37
36
10
30
32
34
28
21
19
17
1820
16
Note:
Early models
used a
Diaphragm(19),
Dust Shield(16)
Service
Piston(17), and
15
o-ring(21)
35
11
12
2
31
33
26
24
22
20A
18
29
15
27
13
14
25
23
17A
1
9
8
7
6
5
4
BODY .........................................1
VALVE COVER ...............................2
RETAINING RING ............................3
EXHAUST COVER ...........................4
O-RING ........................................5
O-RING ........................................6
VALVE SPRING ..............................7
VALVE RETAINER ...........................8
VALVE ASSEMBLY ..........................9
CAP SCREWS .............................10
O-RING .....................................11
O-RING ......................................12
RELAY PISTON ............................13
RETURN SPRING .........................14
RETAINING RING ..........................15
DUST SHIELD (IF FITTED) ...............16
EXHAUST PISTON (ORIGINAL STYLE) .17
EXHAUST PISTON (NEW STYLE) ....17A
EXHAUST PISTON O-RING ..............18
EXHAUST DIAPHRAGM (IF FITTED) ....19
3
SERVICE PISTON (ORIGINAL STYLE -
REQUIRED O-RING 21) ..................20
SERVICE PISTON (NEW STYLE -
DOES NOT REQUIRE O-RING) ........20A
SERVICE PISTON O-RING (IF FITTED) 21
SPRING .....................................22
SPRING CAGE .............................23
BLEND BACK PISTON ....................24
O-RING ......................................25
O-RING ......................................26
O-RING ......................................27
PROPORTIONING PISTON ...............28
O-RINGS ...................................29
RETAINING RING ..........................30
O-RING .....................................31
INLET VALVE SEAT .......................32
INLET VALVE ...............................33
VALVE SPRING ............................34
SEALING RING ............................35
EXHAUST COVER SCREW ..............36
EXHAUST COVER .........................37
FIGURE 10 - BP-R1™ BOBTAIL BRAKE PROPORTIONING RELAY VALVE
4. Connect the tractor service and emergency “glad
hands” (hose couplings) to hose couplings that have
been plugged, or alternatively , to a trailer. Build the tractor system air pressure to governor cut-out and make 4
to 5 full brake applications. Check the air fi ttings at the
BP-R1™ valve for leakage. Tighten as needed.
5. With the trailer supply valve (dash control w/red octagonal button) and system park control (dash control
with yellow diamond button) activated for tractor/trailer
operation, apply , hold, then release the brakes several
times varying the application pressures while watching the reaction of the gauges installed on the BP-R1
valve. Check that a prompt application occurs and that
it can be held then promptly released.
6
™
6. Check the BP-R1™ valve differential pressure by applying 10 psi to the service port and noting the pressure
registered at the delivery port. Subtract delivery port
pressure from the 10 psi service pressure to obtain the
differential. Compare the measured differential with the
™
pressure specifi ed for the BP-R1
valve part number.
Note: For BP-R1™ valves not incorporating a relay
piston return spring (14), the measured differential
should be approximately 4 psi. When a spring is in use,
the differential will be higher (see the I.D. washer also
for the differential).
7. Make and hold a full (100 psi or greater) brake
application and note that full pressure is delivered to
the chambers.
8. Activate the dash mounted trailer supply valve for
bobtail tractor operation. Then make a slow brake
application, increasing the pressure at the BP-R1
™
valve service port to 20 psi while watching the reaction
at the delivery port gauge. Note that delivery pressure
rises to approximately 5 to 10 psi and remains constant
while service pressure continues to rise to 20 psi.
Release the application.
9. Make another brake application and slowly increase
the pressure at the BP-R1™ valve service port to between 60 and 70 psi while observing the gauge installed
at the delivery port. Note that when service port pressure rises to between 20 and 30 psi, delivery pressure
begins to rise above the initial pressure noted in step
6. The rise of delivery pressure should be at a proportioned rate of approximately 3:1. At 70 psi service
pressure, delivered pressure should be 15 to 25 psi.
10. Make a full brake application and note that both test
gauges register the same pressure.
11. Drain air pressure from all vehicle reservoirs and
remove the test gauges from the BP-R1™ valve.
LEAKAGE TESTS
1. Build the air system pressure to governor cut-out. With
the dash mounted trailer supply valve activated for
tractor/trailer operation, apply a soap solution to both
exhaust ports (one in the cover and one in the body).
The leakage noted should not exceed a 1" bubble in
less than 3 seconds at any exhaust port.
2. Make and hold a full brake application and apply a
soap solution to both exhaust ports and around the
cover where it joins the body . The leakage noted should
not exceed a 1" bubble in less than 3 seconds at any
exhaust port.
VALVE REMOVAL
1. Park the vehicle on a level surface and block the wheels
and/or hold the vehicle by means other than the air
brakes.
2. Drain the air pressure from all vehicle reservoirs.
3. Identify and mark or label all air lines and their
respective connections on the valve to facilitate ease
of installation.
4. Disconnect all air lines.
5. Remove the valve from the vehicle.
VALVE INSTALLATION
1. Install all air line fi ttings and plugs making certain thread
sealing material does not enter the valve.
2. Install the assembled valve on the vehicle.
3. Reconnect all air lines to the valve using the identifi ca-
tion made during VALVE REMOVAL (step 3).
4. After installing the valve, test all air fi ttings for excessive
leakage and tighten as needed.
DISASSEMBLY
GENERAL
The following disassembly and assembly procedure is
presented for reference purposes only and presupposes
that the appropriate maintenance kit is on hand at the time
of disassembly . The instructions provided with the maintenance kit should always be used in lieu of those presented
here. Refer to Figure 10 throughout the disassembly and
assembly procedure.
Caution: The BP-R1™ valve may be lightly clamped in a
bench vise during disassembly, however, overclamping will cause 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’s body.
1. Remove all air fi ttings and plugs from the valve.
2. Mark the relationship of the valve cover to the body and
if the valve is equipped with a mounting bracket, mark
the relationship of the bracket to the cover.
3. While holding the exhaust cover (4), remove and
discard the retaining ring (3) that secures it to the body
(1).
4. Remove and discard the exhaust cover (4) along with
both o-rings (5 & 6).
5. Remove and discard the valve spring (7), valve retainer
(8), and the valve assembly (9) from the body (1).
6. Remove and retain the four cap screws (10) that secure
the cover (2) to the body (1).
7. Separate the cover (2) from the body (1), then remove
and discard the sealing ring (35) and o-ring (11).
8. Remove and retain the relay piston (13) and relay piston
spring (14) from the body (1).
Note: The relay piston spring, item 14 is not used in
all valves.
7
9. Remove and discard the o-ring (12) from the relay
piston (13).
10. Remove and discard dust shield (16), if fi tted, and the
retaining ring (15) from the valve cover (2), then remove
and discard the exhaust piston (17 or 17A).
1 1. Remove and discard the exhaust piston o-ring (18) and
the exhaust diaphragm (19), if fi tted.
12. Remove and discard the service piston (20) and its
o-ring (21) from the valve cover (2).
13. Remove the spring (22) and spring cage (23) from the
valve cover (2). Discard the spring and retain the spring
cage.
14. Use shop air at the control port to extract the blend back
piston from the valve cover (2). Retain the blend back
piston (24), then remove and discard both o-rings (25
& 26).
15. Remove and retain the proportioning piston (28) from
the valve cover (2), then remove and discard both
o-rings (27 & 29).
16. While holding the inlet valve seat (32) in place, remove
and discard the retaining ring (30) from the proportioning piston (28).
17. Remove the inlet valve seat (32), the inlet valve (33),
and the valve spring (34) from the proportioning piston
(28), then remove and discard the o-ring (31) from the
valve seat (32). Discard the valve and spring (33 & 34)
also.
18. Remove and discard the exhaust cover screw (36) and
exhaust cover (37).
6. Make certain the air channel running between the top
surface of the body (1) and its supply port is clear and
free of obstruction.
7. Make certain all air channels and exhaust passages in
the valve cover (2) are clear and free of obstruction.
8. Inspect the pipe threads in the body (1) and valve cover
(2). Make certain they are clean and free of thread
sealant.
9. If the valve was equipped with a relay piston spring
(14), inspect it for signs of corrosion, pitting and cracks.
Replace as necessary.
10. Inspect all air line fi ttings for corrosion and replace
as necessary. Make certain to remove all old thread
sealant before reuse.
ASSEMBLY
1. Prior to assembly , lubricate all o-rings (identify by using
Figure 1 1), seals, and pistons as well as body and cover
bores, using the lubricant provided with the Bendix
maintenance kit. Use all of the lubricant and spread it
evenly on the rubbing surfaces.
2. Install the o-ring (31) on the inlet valve seat (32).
I.D."
CLEANING & INSPECTION
1. Using mineral spirits or an equivalent solvent, clean and
thoroughly dry all metal parts. Do not damage bores
with metal tools.
2. Wash all non-metallic components (key nos. 4, 12, 17,
20, 23, 24, 28, 32) 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.
Superfi cial corrosion and/or pitting on the exterior por-
tion of the body (1) and cover (2) is acceptable. Replace
the entire valve if the interior of the body or cover exhibit
signs of corrosion or pitting.
4. Inspect each non-metallic component for cracks, wear
or distortion. Replace the entire valve if these conditions
are found.
5. Inspect the bores of both the body (1) and cover (2)
for deep scuffi ng or gouges. Replace the entire valve if
either are found.
8
W"
O.D."
O-RING IDENTIFICATION
KEY NO. I.D. O.D. W
5 .8620 1.068 .103
6 1.424 1.630 .103
11 3.487 3.693 .103
13 3.234 3.512 .139
18 1.356 1.496 .070
21 1.176 1.316 .070
25 1.112 1.318 .103
26 .7370 .9430 .103
27 .4120 .5520 .070
29 .7390 .8790 .070
31 .4890 .6290 .070
FIGURE 11 - O-RING IDENTIFICATION
3. Install the small end of the inlet/exhaust valve spring
(34) over the rubber of the valve (33), making sure the
spring coils rest on the valve’s four tabs. Note: Both
ends of spring (34) are the same diameter on valves
manufactured after June 1990.
4. Insert the spring and valve into the valve seat (32),
making sure the four tabs are within the seat’s bore.
5. Insert the valve, seat and spring assembly into the
proportioning piston (28).
6. While holding the seat (32) in place, install the retaining
ring (30) to secure it in the piston (28). Make certain the
retaining ring is fully seated in its groove. Make sure
the valve is straight against the exhaust seat and free
to move.
7. Install both the large and small diameter o-rings (27 &
29) on the proportioning piston (28).
8. Install both the large and small diameter o-rings (25 &
26) on the blend back piston (24), then insert the small
diameter of the proportioning piston (28) into the small
diameter end of the blend back piston (24).
9. Carefully insert the assembled proportioning and blend
back pistons (24 & 28) to the edge of the bore in the
cover (2). Do not cut or pinch the o-rings.
10. With the bore of the cover facing up, install the spring
cage (23) in the blend back piston (24) so that its fl at
side rests against the blend back piston (its depressed
side out towards spring (22)).
11. Install the service piston (20) over the spring (22) in
the cage (23) so that its coils are within the l.D. of the
cage.
12. Install o-ring (18) on exhaust piston (17A).
13.Place exhaust piston on service piston with its six ribbed
side facing the service piston. Then install both pistons
while pushing the proportioning and blend back pistons
(28 & 24) all the way into the cover.
14. Install the retaining ring (15), making certain it is fully
seated in its groove.
15. Install the exhaust cover (37) using screw (36) to retain
it. Torque the screw to 8 to 15 lb. in.
16. Install the valve retainer (8) on the inlet and exhaust
valve (9) so that the fl ange of the retainer (8) surrounds
the rubber portion of the valve. Install the inlet and
exhaust valve in the body (1).
17. Install the inlet and exhaust valve return spring (7) in
the body (1).
18. Install the large and small diameter o-rings (5 & 6) in
the exhaust cover (4), then install the exhaust cover
in the body (1), taking care not to damage the o-rings.
Hold the exhaust cover in place.
19.While depressing the exhaust cover (4), install the
retaining ring (3) in the body (1). Make certain the
retainer (3) is fully seated in its groove in the body.
™
20. If the BP-R1
valve was equipped with a relay piston
return spring (15), install the spring in the body, large
diameter fi rst.
21. Using lubricant to hold them in place, install the large
and small sealing rings (11 & 35) on the cover (2).
22.Install the o-ring (12) on the relay piston (13), then install
the piston in the body (1).
23. After noting the relationship marks made prior to disassembly , install the mounting bracket (not illustrated) on
the cover (2) then secure the cover (2) and mounting
bracket on the body (1) using the four cap screws (10).
Torque the cap screws to 120 to 150 lb. in.
24.Install all air line fi ttings and plugs making certain thread
sealing material does not enter the valve.
25. Install the BP-R1™ valve on the vehicle and perform
the Operation and Leakage Tests before returning the
vehicle to service.
9
101112
BW1624 © 2009 Bendix Commercial Vehicle Systems LLC. All rights reserved. 6/2009 Printed in U.S.A.
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