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Repair
32
333011D
Piston Repair
1. Prepare the gun for service, page 28.
2. Remove the air cap, page 29. Remove the gun
shroud (26).
3. Remove the jam nut (16a), actuator arm (15), and
adjustment nut (16b). See F
IGURE
30.
4. Remove piston cap (13) and spring (12) from the
rear of the gun.
5. Push on the piston rod (11) to push the piston out
the back of the gun.
6. Inspect the o-rings (11d, 11e, 11f, 11g) for damage.
See Table 3 and F
IGURE
29.
7. Lubricate the o-rings (11d, 11e, 11f, 11g) with
non-silicone grease, Part No. 111265. Do not
over-lubricate.
8. Align the two stems (11c) with the holes in the gun
body and press the piston assembly into the back of
the gun until it bottoms. Install piston cap (13) and
spring (12).
9. Install and adjust the actuator arm, page 32.
Adjust the Actuator Arm
NOTE:
The seat housing (4) must be in place when
removing or installing the jam nut and actuator arm.
See F
IGURE
30.
1. Install the adjustment nut (16b), actuator arm (15),
and jam nut (16a) onto the piston rod (11b).
2. Position the parts so there is a 0.125 in. (3 mm) gap
between the actuator arm (15) and the fluid packing
rod nut (E). This allows the atomizing air to actuate
before the fluid.
3. Tighten the adjustment nut (16a) against the actua-
tor arm (15). Check that the 0.125 in. (3 mm) gap
has been maintained. Tighten the jam nut (16a).
4. Test gun resistance, page 22.
5. Install the gun shroud (26) and air cap/tip guard
assembly (25), page 29.
6. Install the gun onto the manifold. See page 29.
F
IG
. 29 . Piston O-Rings
WLD
WLD
11a
11d
11c
11f
11e
11g
11b
11e
11g
11f
11d
Atomizing Air Side
Fan Air Side
Table 3. Piston O-Rings
Description
Function
Shaft O-Ring
(11g)
Seals cylinder air along the piston rod
(34b). Replace if air leaks along rod.
Front O-Ring
(11e)
Air shutoff seal. Replace if air leaks from
air cap when gun is de-triggered.
Back O-Ring
(11f)
Separates cylinder air from fan and atom-
izing air.
Piston O-Ring
(11d)
Replace if air leaks from small vent hole
at back of manifold when gun is triggered.
O-rings included in air seal repair kit 24W390.
F
IG
. 30 . Actuator Arm Adjustment
WLD
16a
15
16b 11b
E
0.125 in. (3 mm) gap