Bendix Commercial Vehicle Systems PP-DC PARK CONTROL VALVE 6/07 - Manual (Page 4)

4
LEAKAGE AND OPERATIONAL TESTS
To perform the tests that follow, connect two separate
120 psi air sources to the Bendix
® PP-DC ® valve supply
ports. Tee an accurate test gauge into the supply lines,
and provide for a means to control supply line pressure.
Connect a small volume with a gauge to the delivery port.
LEAKAGE TEST
1. Supply the valve with 120 psi from the primary reservoir
supply port. With the button out, coat the exhaust port
and the plunger stem with a soap solution. Leakage
should not exceed a 1” bubble in fi ve (5) seconds. There
should be no leakage from the secondary reservoir
supply port.
2. With the button out, supply the valve with 120 psi from
the secondary reservoir supply port. There should be
no leakage from the primary reservoir supply port.
3. With the button in, coat the exhaust port and the plunger
stem with a soap solution. Leakage at both areas should
not exceed a 1” bubble in three (3) seconds.
OPERATIONAL TEST
1. With the button out, supply either supply port with
120 psi of air. Then push the button in. Air pres sure
should rise in the delivery volume equivalent to supply
pressure.
2. Pull the button out. Delivery pressure should exhaust
to 0 psi.
3. Build each supply source to 120 psi. Decrease supply
pressure at the secondary service reservoir supply port
at a rate of 10 psi per second. Primary supply pressure
and delivery pressure should not drop below 100 psi.
Repeat the test for decreasing primary service reservoir
pressure.
4. Build each supply source to 120 psi. Then decrease
both supply pressures to below 20–40 psi. The button
should automatically “pop” out when pressure drops
within that range.
If the PP-DC park control valve fails to function as
described, or if leakage is excessive, repair the valve or
replace it at the nearest authorized Bendix
® parts outlet.
REMOVAL
1. Identify and mark or label all air lines and their
connections on the valve.
2. Remove the PP-DC valve from the vehicle and save
the mounting hardware.
INSTALLATION
1. Install the Bendix PP-DC valve in its location on the
dashboard. Using the mounting hardware saved in
“REMOVAL,” secure the valve to the vehicle.
2. Reconnect all air lines to the valve using the
identifi cation made in “REMOVAL.”
3. Perform “LEAKAGE AND OPERATIONAL TESTS”
before placing the vehicle back in service.
DISASSEMBLY
The disassembly and assembly procedures that follow
are for reference only. Always have the appropriate
maintenance kit on hand and use its instructions in lieu
of those presented here. Refer to Figure 7 throughout the
procedure.
1. Turn the button counterclockwise to remove it from the
plunger stem.
2. Remove the four screws that secure the cover to the
body, and remove the cover.
3. Pull the plunger stem to remove the plunger and the
guide spool from the body.
4. Remove plunger spring(6) and discard.
5. If necessary, use a screwdriver to carefully remove the
check valve seat from the body. Be sure not to damage
the check valve seat or the body.
6. Remove and discard check valve seat o-rings(7)
and (8).
7. Turn the body upside down and gently tap it on a fl at
surface to remove check valve(9). Discard the check
valve.
8. Remove the guide spool from the plunger. Remove and
discard o-ring(1) from the guide spool.
9. Remove and discard o-rings(2), (3) and (5) from the
plunger. Also remove and discard exhaust seal(4).
CLEANING & INSPECTION
1. Wash all metal parts in mineral spirits and thoroughly
dry.
2. Inspect all re-usable parts for excessive wear or
damage. Inspect the body for gouges or deep scuffi ng.
Replace key numbers 1-9 (and any parts not determined
usable) with genuine Bendix
® replacements.
ASSEMBLY
Before assembly, lubricate all o-rings, o-ring grooves,
rubbing surfaces and bores with Bendix silicone lubricant
(Bendix piece number 291126) or equivalent.
1. Place check valve(9) into its seat in the body with its
fl at surface facing upward. If necessary, reach into the
body to make sure the valve is seated evenly in the
bore.
2. Install o-rings(7) and (8) on the check valve seat and
install the check valve seat into the body. Make sure
the seat is fully seated—its surface should be even with
the body’s surface.
3. Install plunger spring(6) into the body. Make sure it
stands upright and is seated properly in the body bore.
(It should surround the protrusion or “lip” at the bottom
of the body bore.)
4. Install o-rings(2), (3), (5) and exhaust seal(4) onto the
plunger. Then install the plunger into the body. Line up
the plunger’s index tabs with the spaces in the body
bore for ease of installation.