Bendix Commercial Vehicle Systems AD-9 AND AD-9 IPC AIR DRYERS 4/11 - Manual (Page 14)

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4. Make certain that all purge valve housing and end cover
passages are open and free of obstructions.
5. Inspect the pipe threads in the end cover. Make certain
they are clean and free of thread sealant.
6. Inspect the purge valve housing bore and seats for
excessive wear and scuffi ng.
7. Inspect the purge valve piston seat for excessive wear.
8. Inspect all air line fi ttings for corrosion. Clean all old
thread sealant from the pipe threads.
9. All o-rings removed should be discarded and replaced
with new o-rings provided in appropriate kit(s).
Any component exhibiting a condition described in step 1
to 8 should be replaced.
ASSEMBLY
The following assembly procedure is presented for
reference purposes and presupposes that a major rebuild
of the Bendix
® AD-9 ® or AD-9 ® IPC air dryer is being
undertaken. Several replacement parts and maintenance
kits are available which do not require full disassembly. The
instructions provided with these parts and kits should be
followed in lieu of the instructions presented here. Refer
to Figures 7, 8 and 9 during assembly.
Purge Valve Housing Assembly
1. Prior to assembly, coat all o-rings, o-ring grooves, and
bores with a generous amount of the lubricant included
in the maintenance kit. See Figure 7, illustration D.
A. Install the quad-ring in its groove on the O.D. of the
purge piston. Place the return spring in the bore of
the purge valve housing. Insert the purge piston into
the I.D. of the return spring. Place the purge valve
guide onto the shoulder bolt followed by the purge
valve. Using a ratchet or wrench, screw the purge
valve, purge valve guide and shoulder bolt into the
purge housing until it bottoms. This will require a tool
to hold the top of the purge piston from rotating as the
shoulder bolt is screwed into the bottom of the purge
piston to complete the purge valve assembly. Torque
the shoulder bolt to 60–90 in. lbs.
B. Install the o-rings on the purge valve housing, placing
each in its appropriate location. Note the medium
o-ring is not used on Discharge Line Unloaded
(DLU) models. If the exhaust cover was removed
during disassembly, install it on the purge valve
assembly making certain the “bubble” portion is
positioned over the thermostat. Install the assembled
purge valve housing in the end cover. Make certain
to orient both parts such that the connector is
approximately 10 degrees clockwise from the supply
port, while making certain the purge valve housing is
fully seated against the end cover. Secure the purge
valve housing to the end cover using the three 1/4"
self-tapping screws. Start all three screws by hand
then torque to 50–80 in. lbs.
Delivery Check Valve Assembly
The current style AD-9 ® air dryer end cover has a
horizontal delivery check valve while earlier styles
contained a vertical design. Identify the style of AD-9
®
air dryer end cover and proceed to the appropriate step
for installation.
See Figure 7, illustration E.
Vertical Delivery Check Valve –
1. Assemble the spring to the retainer and check valve.
Ensure the spring is fully seated on the retainer and
the check valve.
2. Lubricate the entire spherical surface of the check valve
and bore chamfer of the check valve housing with the
lubricant provided in the kit.
3. Place the retainer, spring and check valve sub-
assembly into the check valve housing. Press the
retainer using a 7/16" deep socket with a 3/8" drive,
and a vise as shown in Figure 12.
4. Inspect the bore of the end cover. Make certain that the
end cover passage is open and free of obstructions.
5. Install the o-ring on the outer body of the delivery check
valve assembly. Ensure the o-ring is seated properly
and not twisted. Lubricate the o-ring.
6. Install the delivery check valve assembly into the end
cover. Torque to 200–250 in. lbs.
Horizontal Delivery Check Valve –
1. Lubricate the o-ring and the long check valve body with
the lubricant provided. Use only the lubricant contained
in the kit.
2. Install the o-ring on the long check valve body. Push
the o-ring down, over the 3 guide lands until it is in the
o-ring groove. Ensure the o-ring is seated properly
and not twisted.
3. Install the spring on the white check valve body so that
the small coils of the spring slip over the check valve
body.
DELIVERY CHECK
VALVE BODY
7/16" DEEP
SOCKET WITH A
3/8" DRIVE
APPLY LUBRICANT
BENCH VISE
CHECK
VALVE
SPRING
SPRING
RETAINER
FIGURE 12 - VERTICAL DELIVERY CHECK VALVE