Service

Repairing the Air Valve

Tools Required

DTorque wrench

DTorx (T20) screwdriver or 7 mm (9/32”) socket

DNeedle-nose pliers

DO-ring pick

DLithium base grease

NOTE: Air Valve Repair Kits 236273 (aluminum center housings) and 255061 (stainless steel center hous- ings) are available. Refer to page 27. Parts included in the kit are marked with a symbol, for example (4{H). Use all the parts in the kit for the best results.

Disassembly

WARNING

To reduce the risk of serious injury whenever you are instructed to relieve pressure, always follow the Pressure Relief Procedure on page 12.

1.

Relieve the pressure.

2.

With a Torx (T20) screwdriver or 7 mm (9/32”)

 

socket wrench, remove the six screws (3), air

 

valve cover (2), and gasket (4). See Fig. 7.

32

2 4{H

Torque to 50–60 in-lb

2

 

 

 

(5.6–6.8 NSm).

 

 

 

 

04618B

Fig. 7

 

 

 

 

 

 

 

 

1

See Detail at right.

5

3. Move the valve carriage (5) to the center position

and pull it out of the cavity. Remove the valve

2 Grease.

3 Grease lower face.

2 H{6

block (7) and o-ring (6) from the carriage. Using a

needle-nose pliers, pull the pilot block (18) straight

up and out of the cavity. See Fig. 8.

4. Pull the two actuator pistons (11) out of the bear-

ings (12). Remove the u-cup packings (10) from

the pistons. Pull the pilot pins (16) out of the

bearings (15). Remove the o-rings (17) from the

pilot pins. See Fig. 9.

5. Inspect the valve plate (8) in place. If damaged,

use a Torx (T20) screwdriver or 7 mm (9/32”)

socket wrench to remove the three screws (3).

Remove the valve plate (8) and, on aluminum

center housing models only, remove the seal (9).

See Fig. 10.

6. Inspect the bearings (12, 15) in place. See Fig. 9.

The bearings are tapered and, if damaged, must

be removed from the outside. This requires disas-

sembly of the fluid section. See page 23.

7. Clean all parts and inspect for wear or damage.

Replace as needed. Reassemble as explained on

page 17.

3 H{7

H{18 3

5 1

11

16

04900

Fig. 8

16 308550

Page 16
Image 16
Graco 308550ZAD Service, Repairing the Air Valve, Tools Required, Disassembly, Relieve the pressure