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.

DELIVERY CHECK

VALVE BODY

APPLY LUBRICANT

CHECK

VALVE

6.

Inspect the purge valve housing bore and seats for

 

excessive wear and scuffing.

7.

Inspect the purge valve piston seat for excessive wear.

8.

Inspect all air line fittings 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.

SPRING

SPRING

RETAINER

7/16" DEEP

SOCKET WITH A

3/8" DRIVE

BENCH VISE

FIGURE 12 - VERTICAL DELIVERY CHECK VALVE

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.

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BENDIX SD-08-2412 manual Purge Valve Housing Assembly, Delivery Check Valve Assembly