24 307-712
SERVICE
Piston Removal and Repair
1. To disconnect the fluid hose (31) from the cover
plate (41), screw the nut (34) off the adapter (35).
See Fig 21.
2. Notethe position of the trigger adjusting nut (24) for
reinstallation,then screw it off the piston  shaft.
3. Removethe screws (61) and lock washers (82) from
the cover plate (41). Remove the cover plate (41),
spring (38), and retainer cap (74).
4. Unscrew and remove the air valve guide (26) and
needle packing (27) from the gun body (1),
5. Pushon the end of the piston shaft, and remove the
piston assembly.
NOTE: DO NOT remove the uĆcup packing (37) from
the piston shaft except to replace it as removal
will damage this packing.
6. Clean and inspect parts for wear or damage. ReĆ
place parts as needed.
7. When reassembling the piston assembly,lubricate
theoĆrings (30 & 79) and the uĆcup packing (42) on
the piston with petroleum jelly.Pack the spring (38)
withpetroleum jelly. Apply Teflontape to the air valve
guide (26).
8. Install the new packing (27) and guide (26) in the
gun body (1); screw the guide in loosely.
NOTE: DO NOT fully tighten the guide (26) yet. The
guide must be loose to avoid damaging the
packing (27) when pushing the piston shaft
throughthe guide.
9. If replacing the uĆcup packing (37), slide it onto the
piston (42) so the lips of the packing will face toĆ
wards the front of the gun when the piston is inĆ
stalled. Then install the bunaĆn oĆring (30) and
Viton oĆring (79) on the piston.
10. Install the piston assembly into the gun body (1),
being careful not to damage the piston's lip seal.
11. Install the retainer cap (74) into the cover plate (41).
12. Install the cover plate (41), spring (38), and retainer
cap(74) with the screws (61) and lock washers (82).
13. Actuate the trigger and tighten the air valve guide
(26) with a wrench.
14. Screw the trigger adjusting nut (24) onto the piston
shaft to its previously noted position.
15. Connect the fluid hose (31) to the adapter (35).
Fig 21
KEY
1GunBody
24 TriggerAdjusting Nut
26 AirValve Guide
27 NeedlePacking
30 BunaĆnOĆRing
31 FluidTube
34 Nut
35 Adapter
37 UĆCupPacking
38 Spring
41 CoverPlate
42 Piston
61 Screws
74 RetainerCap
79 VitonOĆRing
82 LockWashers
26
Apply
Teflon
tape
24
31 34
27
41
35
82
61
30
79
37
38
74
Packwith
lubricant
42
1