Displacement Pump
NOTE: Packing Repair Kit 235–703 is available. Refer-
ence numbers of parts included in the kit are marked
with an asterisk, i.e., (121*).
NOTE: To minimize down time, and for the best spray-
er performance, check the motor brushes (see page
21) and clean the transducer (see page 30) whenever
you repack the pump. Replace these parts as needed.
Removing the pump (See Fig.17)
WARNING
INJECTION HAZARD
To reduce the risk of serious injury,
whenever you are instructed to relieve
pressure, follow the Pressure Relief
Procedure on page 8.
1.
Relieve pressure.
2.
Flush the pump, if possible. Relieve pressure. Stop
the pump with the piston rod (107) in its lowest
position, if possible. To lower the piston rod manu-
ally, rotate the motor fan blades.
3.
Remove the filter (85).
4.
Models 820–206. While pulling upward on the
suction hose (32), unscrew the hose from the inlet
tube (38). Unscrew the drain hose (33) from the
displacement pump nipple (36).
5.
Models 820–208. Remove the suction tube (32).
Unscrew the drain tube (33) from the displacement
pump nipple (36).
NOTE: If repairing only the intake valve assembly, go
to intake valve repair, on page 23.
6.
Use a screwdriver to push the retaining spring (18)
up and push out the pin (17).
7.
Loosen the screws (21). Remove the pump (20).
Installing the pump (See Fig. 17 and 18)
1.
Lightly grease or oil the transducer (29). See Fig.
29. Guide the pump over the alignment pins and
pressure transducer. Tap it into position with a soft
hammer. Tighten the screws (21) to 50 ft-lb (68
N.m).
2.
Align the hole in the rod (107) with the connecting
rod assembly (15). Use a screwdriver to push the
retaining spring (18) up and push in the pin (17).
Push the retaining spring (18) into place around
the connecting rod.
WARNING
MOVING PARTS HAZARD
Be sure the retaining spring (18) is firmly
in the groove all the way around, to pre-
vent the pin (17) from working loose due
to vibration.
See Fig. 18.
If the pin works loose, parts could be projected into
the air and cause serious injury or property dam-
age, including the pump connecting rod or bearing
housing.
3.
Replace the o-ring (27) if it is worn or damaged.
See page 32. Reconnect the suction and drain
hoses (32,33). Install the front cover (13).
4.
Tighten the packing nut (102) just enough to stop
leakage, but no tighter. Fill the packing nut/wet-cup
1/3 full with Graco TSL. Push the plug (123) into
the wet-cup.
