Repairing the Air Control Valve

Service

NOTE: Air Valve and Pilot Valve Repair Kit 220656 is available. See page 38 to order. Parts included in the kit are marked with an asterisk, for example, (40p*).

Use all the parts in the kit for the best results.

Disassembly

1.Relieve the pressure.

5.Thread one spool (40c) onto the stem (40d) and insert it into the center housing (40a); be careful not to dislodge the u-cups (40j) and retainers (40e). Thread the other spool onto the stem. With wrenches on the flats of the spools, apply oppos- ing force and tighten until snug; 7 to 13 in-lb (0.79 to 1.47 NSm). Do not overtighten.

WARNING

PRESSURIZED EQUIPMENT HAZARD

To reduce the risk of a serious injury whenever you are instructed to relieve pressure, follow the Pres- sure Relief Procedure on page 10.

2.Cut a small slit in the tube ends (72*, 42*, 40p*) and disconnect them from the pilot valve fittings (5h), air valve tees (40n), and barb fittings (40s). See Fig. 8.

3.Remove the valve end housings (40b) by unscrew- ing the screws (40k) and nuts (40m).

4.Center the valve spools (40c) in the housing (40a). Remove the spools and stem (40d) by applying opposing force with wrenches on the spool (40c) flats.

5.If the air filter (40q) needs cleaning or replace- ment, unscrew the filter housing (40r) and remove the filter. To clean them, soak the filter housing and the filter in solvent until they are clean. Blow them dry with low pressure air [under 30 psi (207 MPa, 2.1 bar)]. Press fit the filter into the housing, using 40 to 60 lb (18 to 27 kg) of force. Refer to Fig. 8. Apply sealant to the filter housing threads and turn it into the center housing (40a).

Assembly

1.Apply lithium-base grease to all o-rings, u-cups, gaskets and to the complete spool assembly be- fore installing them.

2.Remove the seal retainers (40e) from each side of the center housing (40a). Replace the u-cup (40j*), with the lips facing into the housing. Install the re- tainers with the flat side facing into the housing.

3.Replace the spools (40c) if damaged. Replace the o-ring (40h*) and u-cup (40i*) on each spool, being sure to seat them in the grooves. Install the u-cup with the lips facing towards the housing (40a).

4.Apply medium strength thread sealant to the spool stem (40d) threads. Remove the excess sealant.

CAUTION

Do not overtighten the spools (40c) as this can shear the spool threads.

6.Replace the gasket (40f*) in each end housing (40b) and the o-ring (40g*) on each end housing shoulder.

7.With the mufflers facing down, install the end housings (40b), onto the center housing (40a); be careful not to move the spool and dislodge the u- cups (40j) and retainers (40e). Secure the end housings with the four screws (40k) and nuts (40m), torquing them to 2.2 to 3.7 ft-lb (3 to 5 NSm).

CAUTION

If mufflers (38) are replaced, they must be installed with the lock rings (39) to avoid damage to the spool and o-rings during operation.

8.Replace the two o-rings (40h*) in the center hous- ing (40a).

9.Install the air valve on the pump with the four cap screws (43). Torque them alternately and evenly to 2.2 to 3.7 ft-lb (3 to 5 NSm).

10.Connect the new tubes (72*, 42*, 40p*) to the pilot valve fittings (5h), air valve tees (40n), and barb fittings (40s), as shown in Fig. 8.

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