Graco 278680, Instructions Manual, Page: 16 / 28

Displacement Pump Replacement
16 332257A
Installation
1. Extend pump piston rod full. Apply grease to top of
pump rod at (A) or inside connecting rod (43). Install
jam nut (29) on pump threads.
2. Install pump rod (A) into connecting rod (43).
3. Install pump pin (32). Slide retainer spring (31)
down into groove over pump pin.
4. Push pump (41) up until pump threads engage.
5. Screw in pump until threads are flush with top of
drive housing opening.
6. Align pump outlet (P) to back.
7. Turn jam nut (29) counter-clockwise until it stops.
Tighten jam nut by hand, then tap 1/8 to 1/4 turn
with a 20 oz (maximum) hammer to approximately
75 ft-lb (102 N•m).
8. Install suction tube (60) and high pressure hose
(45). Tighten fittings.
9. Fill packing nut with Graco TSL until fluid flows onto
top of seal.
10. Replace cover (70) over screws. Push cover down
into place. Tighten screws (12).
If pump pin works loose, parts could break off due to
force of pumping action, project through the air, and
result in serious injury or property damage. To avoid,
ensure the retainer spring is installed properly.
NOTICE
If the pump jam nut loosens during operation, the
threads of the drive housing will be damaged.
29
A
43
ti21094a
43
A
ti21094a
32
31
ti6111a
P
ti21087a
29
ti21097a
60
45
ti21096a
ti21086a