Bendix Commercial Vehicle Systems BP-1 BRAKE PROPORTIONING VALVES - Manual (Page 6)

6
REMOVAL OF BP-1 ™ FRONT VALVE FROM
VEHICLE
1. Secure the vehicle on a level surface by means other
than the brakes.
2. Drain the air system completely making sure all reservoirs
are at atmospheric pressure.
3. Remove and identify the air lines from the BP-1 ™ front
valve. The BP-1 ™ front valve is usually located along the
frame rail between the brake valve and front axle.
4. Remove the two bolts attaching the BP-1 ™ front valve to
the vehicle and move the valve to a bench.
5. Clean the exterior of the valve taking care to prevent
contaminates from entering the open ports of the valve.
DISASSEMBLY OF BP-1 ™ FRONT VALVE
(REFER TO FIGURE 5)
1. Remove the four Sems screws from the cover.
Caution: Hold cover down against spring load and
release gently when screws are removed. Retain the
screws and the metal tag with ‘BP-1 Front’ stamped on
it. Separate the cover from the body. Remove and
discard o-ring(7).
2. Remove the upper piston from the cover and the piston
spring(4) and lower piston from the body.
3. With a pair of needle nose pliers grasp the end of the
valve spring(6) inside the lower piston and remove by
pulling and turning the spring in a clockwise manner.
4. Remove the inlet/exhaust valve(5) from the lower piston.
5. Remove the o-rings(1), (2), (3) from the pistons.
CLEAN & INSPECT
1. Wipe the interior of the body, cover and the pistons
with a clean dry cloth to remove any contaminates.
2. Visually inspect all components for cracks, scoring, or
damage of any kind. If any of these conditions exist,
the valve should be replaced.
ASSEMBLY (REFER TO FIGURE 5)
1. Coat bore surfaces of both the cover and the body with
a light film of silicone lubricant.
2. Lubricate the four o-rings in kit with the same material
as Step 1.
3. Install o-rings(1) and (2) on the lower piston, o-ring(3) on
the upper piston and o-ring(7) on the cover. Refer to Figure
4.
4. Install the large end of the upper piston into the bore of
the cover of the valve.
5. Place the inlet/exhaust valve(5) into the I.D. of the lower
piston and retain with valve spring(6). Use needle nose
pliers to install spring(6) by grasping spring on the bar
that intersects the end of the spring and twisting in a
clockwise motion while pressing down.
Caution: Be sure inlet/exhaust valve is seated flat against
the bottom of the piston and the spring is fully
seated below the step on the I.D. of the piston
wall. Refer to Figure 5.
6. Install the lower piston assembly into the body of the
valve. (Large end to enter the bore first.)
7. Install the piston spring into the body of the valve. (Large
diameter of the spring to enter first.)
8. Place the cover and upper piston onto the body so that
the supply port is directly above the control port. Place
the valve on a firm surface and compress the spring by
pushing down on the cover. Hold in this position and
install two of the four 1/4" Sems screws.
9. Place the metal tag stamped ‘BP-1 Front’ onto one of
the remaining 1/4" Sems screws. Install all Sems screws
and torque to 50-80 inch pounds.
10. Reinstall the BP-1 ™ front valve on the vehicle and
reconnect the air lines as identified in ‘Removal’
instructions.
11. Refer to section titled ‘Operational Checks’.
BW1554 © 2004 Bendix Commercial Vehicle Systems LLC All rights reserved. 3/2004 Printed in U.S.A.