3M Graco 50261 Manuel D'instructions page 13

Reassembling the gun
NOTE: To ensure proper alignment of the parts, follow the next steps
in the order they are given.
1. Slide the adapter (4) into the spray housing (2a), and install them
onto the gun body (1). Align the housing with the slot and lip (A)
on the gun body (1). See Fig. 21 page 10.
2. Tighten the hex nut (9) onto the adapter (4) hand-tight, then loosen
the nut about one turn so the adapter (4) and spray housing sit
loosely in the gun body.
3. Check the fluid needle (13) for damage or excessive wear.
Replace needle tip or entire needle if necessary. If replacing
needle tip, use low strength thread locker on needle tip threads.
4. Lubricate the outside of the new air valve assembly (26) and place
it on the fluid needle (13), against the nut (B). See Fig. 29.
This helps align the entrance of the air valve stem into the inside
diameter of the u-cup (16) without damaging the u-cup lid.
5. Install the fluid needle (13) and the air valve assembly (26) into the
back of the gun.
Fig. 29
Service
6. Install a new air valve spring (22). Point the gun down to centre
7. Replace and install a new needle spring (23). Install fluid
8. Install the trigger (10), pivot pin (17), wave washer (18), and
9. To avoid galling of the fluid nozzle in the spray housing (2a) apply
10.
11. Install the pattern adjustment valve assembly (25).
12. To tighten the packing screw (8), turn the screw in until it touches
13. Trigger the gun to test the needle movement. If the needle does
13
14. Install the air cap (14) and air cap retaining ring (15).
15. Make sure the gun fluid packings are sealing properly by spraying
13
the spring (22) and tighten the fluid nut (19) to 14-15 N•m
(125-135 in-lb).
adjustment knob (21).
screw (11). Torque the screw to 2.3 - 3.4 N•m (20-30 in-lb).
a thin film of lubricant to the back surface of the nozzle taper
where it seats and also to the nozzle threads. Trigger the gun
while you install the fluid nozzle (12) with the gun tool (28).
Tighten the nozzle securely to 4.5 N•m (40 in-lb) to obtain a
good seal. Do not over torque.
Tighten the hex nut (9) securely to 14-15 N•m (125-135 in-lb).
Torque the nut (25a) to 14-15 N•m (125-135 in-lb).
the fluid packings (5), then tighten one full turn to pre-set the
packings. Loosen the screw, then turn it in until it touches the
packings again.Tighten the screw 1/12 turn more (equal to half
the distance between points on the hex head).
not return after the trigger is released or is slow in returning,
loosen the packing screw (8) until the needle returns freely.
Hand tighten the ring.
solvent at low pressure before fully pressurizing the gun with the
fluid to be sprayed.
If the fluid packings leak, tighten the packing screw (8) slightly
and re-test until the packings and fluid needle seal completely.