Pro 501st Airless Paint Sprayer - Graco Inc.

Displacement Pump Repair
102
101
11. Place a new o-ring (116*) firmly in the cylinder
groove. See Fig. 24.
12. Coat the piston rod and packings with oil. Carefully
slide the assembly into the top of the cylinder
(115). See Fig. 24.
13. Put the manifold in a vise. Full thread the jam nut
(117) onto the cylinder (115). Guide the rod/cylinder
assembly down through the manifold (101).
Screw the cylinder (115) into the manifold. See
Fig. 24.
Torque jam nut (117)
to 73 ft–lb (98 N.m)
Torque cylinder (115)
into manifold (101) to
53 ft–lb (71 N.m)
Torque intake valve (116)
into cylinder (115) to
53 ft–lb (71 N.m)
Piston assembly
107
116*
14. Place the ball guide (120), stop pin (122) and ball
(121*) in the cylinder (115). Screw the intake valve
into the cylinder and torque to 53 ft-lb (71 Nm).
This will also properly torque the cylinder into the
manifold. See Fig. 24.
15. Torque the cylinder jam nut (117) to 73 ft-lb (98
Nm). See Fig. 24.
16. Install the pump. See page 20.
117
115
118
Fig. 24
01072A