34
308-385
Service
Piston Repair (continued)
4. Push on the piston rod (23g) to push the piston
assembly out the back of the gun.
5. Inspect the o-rings (23a, 23b, 23c) and u-cup
packing (23f) for damage. See Fig. 26. Refer to
Fig. 27 to isolate any air leakage problems.
6. Lubricate the o-rings (23a, 23b, 23c) and u-cup
packing (23f) with petroleum jelly.
7. Align the two stems (23d) with the holes in the gun
body and press the piston assembly into the back
of the gun until it bottoms.
Apply a very light coat of lubricant to the o-rings (23a, 23b, 23c)
and u-cup (23f).
Align the two stems (23d) with the holes in the gun body and
press the piston assembly until it bottoms.
Fig. 26
03530
23g
23f
23e
23d
23c
23b
23a
Description Function
O-Ring (23a)
Shaft Air Seal
It seals the cylinder air along the piston
rod. If the air leaks along the piston rod
(23g), replace this o-ring (23a).
O-Ring (23b)
Front Air Seal
It is the air shut-off seal. If the air leaks
from the air cap when the gun is detrig-
gered, replace these o-rings.
O-Ring (23c)
Back Air Seal
It separates the cylinder air pressure from
the fan and atomizing air pressure.
U-cup (23f)
Cylinder Air
Seal
If the air leaks from the small vent hole in
the back of the manifold when the gun is
triggered, replace the u-cup.
Fig. 27
23a
23c
23b
23f
Fan Air Side
Atomization Air Side
03531
8.
Installing the Actuator Arm and Nuts:
a. Install the adjustment nut (36), actuator arm
(19), and jam nut (46) onto the piston rod
(23g). See Fig. 25 on page 33.
b. Thread the jam nut (46) flush with the end of
the piston rod (23g).Tighten the adjustment nut
(36) against the actuator arm (19). When prop-
erly assembled, there should be about a 0.125
in. (3 mm) gap between the actuator arm (19)
and the fluid packing rod nut (U), which allows
the atomizing air to actuate before the fluid
actuates. See Fig. 28. In addition, there should
be 3 to 4 mm of electrode needle travel when
the gun is triggered. If necessary, adjust the
jam nut (46) position to obtain these
dimensions.
NOTE: The jam nut (46) has a slightly larger hex and a
thinner profile than the adjustment nut (36).
There should be a 0.125 in. (3 mm) gap between the actuator
arm (19) and the fluid packing rod nut (U).
Fig. 28
04823
19
U
9. Test the gun resistance as instructed on page 27.
10. Install the gun shroud and air cap assembly.
11. Install the gun onto the manifold and bracket as
instructed on page 39.
