Piston Repair - Graco PRO 5500hc Instructions Manual

Fluid Packing Rod Removal and Repair
(continued)
8. Place the packing nut (28c) and o-ring (28g) on the
fluid rod (28b). The flats on the packing nut must
be facing toward the back of the fluid rod.
9. Fill the entire inner cavity of the spacer (28d) with
petroleum jelly. Place the spacer on the fluid rod
(28b), in the direction shown in Fig. 24. Generous-
ly apply petroleum jelly to the outside of the
spacer.
10. Place the fluid packing (28f), needle packing (28e),
and housing (28a) on the fluid rod (28b) as shown
in Fig. 24.
11. Lightly tighten the packing nut (28c) with the
multi-tool (83). The packing nut is properly tight-
ened when there is 2 lbs. (9 N) of drag force when
sliding the packing housing (28a) assembly along
the shaft. Tighten or loosen the packing nut as
needed.
Apply a very light coat of lubricant to the o-ring (28h).
Fill the inner spacer (28d) cavity with petroleum jelly and gener-
ously lubricate the outside of the spacer .
28f
28e
28b
Fig. 24

Piston Repair

1. Prepare the gun for service as instructed on
page 28.
2. Remove the air cap assembly and the gun shroud.
3. Remove the jam nut (46), actuator arm (19), and
adjustment nut (36). See Fig. 25.
NOTE: The fluid nozzle must be in place when remov-
ing or installing the jam nut and actuator arm.
32 308–442
Service
28h
28a 28d
28g
28c
12. Lubricate the o-ring (28h) on the outside of the
packing housing (28a).
13. Make sure the spring (11) is installed against the
nut (U) as shown in Fig. 24.
14. Install the fluid packing rod assembly (28) into the
gun barrel. Using the multi-tool (83), tighten the
assembly until it is just snug, then check the drag
on the fluid rod. See Fig. 23, page 31.
15. Install the electrode needle, fluid nozzle and resis-
tor stud as instructed on page 30.
16. Install and adjust the actuator arm (19) and jam
nut (46) as instructed on page 33.
17. Test the gun resistance as instructed on page 26.
18. Install the gun shroud and air cap assembly.
19. Install the gun onto the manifold and bracket as
instructed on page 37.
Tighten the packing nut (28c) to 2 lbs (9 N) of drag force.
The spring (11) is not included with the fluid packing rod assembly
(28).
28
Fig. 25
U 11
03224
46 19 36 23g
03904A