3
REMOVAL
1. Block or hold the vehicle by means other than the
brakes.
2. Drain all air brake system reservoirs.
3. Identify, mark, and disconnect all air lines from the
Bendix
®
R-8P
™
pilot relay valve.
4. Remove the R-8P valve from its mount on the vehicle.
DISASSEMBLY
1. Note and mark the position of the valve cover to the
body.
2. Remove the four 5/16"-18 hex screws and separate the
cover from the body.
3. Remove and discard the sealing ring (3) from the body.
4. Remove the piston and spring from the cover and retain
all parts.
5. Remove and discard the o-ring (2) from the piston.
6. Remove the screw, washer, and diaphragm (5) from
the exhaust cover. Discard the diaphragm (5).
7. Remove the four 10-24 screws which secure the
exhaust cover to the body.
8. Remove and discard the inlet exhaust assembly (4)
from the body.
9. Clean all remaining parts in a cleaning solvent
equivalent to mineral spirits. Make certain all surfaces,
bores, and passages are clean and dry.
ASSEMBLY
NOTE: Make certain both piston orifices are
open
and not
clogged. Grease all o-rings, o-ring grooves and bores with
the lubricant (6) provided in this kit.
1. Install diaphragm (5) and diaphragm washer and secure
with screw. Torque screw to 15-25 in-lbs.
2. Install the inlet and exhaust valve assembly (4) in the
valve body. Position exhaust cover assembly so that all
holes are properly aligned and secure with four 10-24
screws. Torque screws to 20-30 in-lbs.
3. Install the sealing ring (3) in the valve body.
4. Install o-rings (1) & (2) on the piston.
5. Install the spring in the valve cover so that the large
diameter end of the spring will rest on the piston.
6. Install the piston (with its o-rings installed) in the valve
cover. NOTE: Make certain the spring is centered and
not binding.
7. Install the valve cover on the valve body in the same
position as marked in Step 1 of "Disassembly". Secure
the cover to the body using the four 5/16" hex head cap
screws. Torque to 120-150 in-lbs.
INSTALLATION
1. Mount the R-8P on the vehicle.
2. Connect the air lines to the R-8P valve using identification
made during Step 3 of "Removal" instructions.
3. Perform "Operating and Leakage Checks" before
placing the vehicle into service.
OPERATING AND LEAKAGE CHECKS
1. Block the wheels and fully charge the air system. Adjust
the brakes.
2. Apply and release the service brakes several times
and check for prompt response of the brakes at all
appropriate wheels.
3. With the air system fully charged, apply a soap solution
to the exhaust of the R-8P valve. Leakage of a 1" bubble
in 5 seconds is permissible.
4. Make and hold a full brake application and again apply
a soap solution to the R-8P exhaust. Leakage of a
1" bubble in three seconds is permissible.
5. With the brakes still applied, apply a soap solution
around the valve where the cover meets the body. No
leakage at this point is permitted.
If the valve is unable to pass these operating and leakage
checks, it is recommended that it be exchanged for a
genuine Bendix
®
remanufactured exchange unit.
