Displacement Pump; Removing The Pump; Reinstalling The Pump; Reassembly Notes - Graco EM 390 Instructions And Parts List

WARNING
To reduce the risk of serious bodily injury, follow the
Pressure Relief Procedure Warning on page 16
before checking or repairing any part of the spray
system. Unplug the sprayer!

Removing the Pump.

1. Flush the sprayer. Relieve pressure.
2. For the upright sprayer, remove the clips (110,114)
and drain tube (125) from the pump.
3. Hold the intake valve (222) steady with a wrench and
unscrew the adapter (38).
4. Unscrew the hose (52).
5. Use a screwdriver to push the retaining spring (33)
aside, and then push out the pin (34).
6. Loosen the locknut (112) and unscrew the pump (58).
55
54
A
33
36
223
112
TORQUE TO
58
70 ft–lb
(95 N.m)
Fig 18–1

Reinstalling the Pump.

1. Rotate the crankshaft (A) so the connecting rod (54)
is in its lowest position. The pump piston rod (223)
should protrude about 1 in. (25 mm) above the pump
cylinder.
2. Screw the pump into the drive housing (55) until the
pin holes are aligned with the pump coupling (36). In-
sert the pin (34). Position the spring (33) so it covers
the ends of the pin.

DISPLACEMENT PUMP

See Fig 18–1.
34
INTAKE VALVE DETAIL
52
207*
10
215
*204
*206
222
TORQUE TO
38
80 ft–lb
(107 N.m)
See Fig 18–1.
Be sure the retaining spring (33) is firmly and com-
pletely in the groove of the connecting rod to prevent
the pin (34) from working loose due to vibration. See
Fig 18–1.
If the pin works loose, it or other parts could break
off due to the force of the pumping action. These
parts could be projected through the air and result
in serious bodily injury or property damage, includ-
ing damage to the pump, connecting rod or bearing
housing.
3. Screw the pump further into the drive housing (55) un-
til it stops at the locknut (112). Unscrew the pump just
until the nipple (10) faces straight back.
4. Torque the locknut (112) to 70 ft–lb (95 N.m).
5. Reassemble the remaining parts, in the reverse order
of removal.
Disassembly.
See Fig 19–1 , except where noted.
1. Remove and disassemble the intake valve (222). If no
further service is needed, reassemble the valve, us-
ing a new gasket (206*). Torque the intake valve to
80 ft–lb (107 N.m). See Fig 18–1.
2. Remove the packing nut (221) and plug (201).
3. Tap the piston rod (223) down with a plastic mallet.
Pull the rod out the bottom of the cylinder (216).
4. Remove the packings and glands from the throat of
the cylinder (216).
5. Clamp the flats of the piston rod (223) in a vise. Un-
screw the retaining nut (214). Unscrew the piston
valve (224) from the rod. Remove all parts from the
piston.

Reassembly Notes

A. Packing Repair Kit 222–587 is available. Parts in-
cluded in the kit are marked with an asterisk (*) in the
text and drawings.
B. Clean all parts thoroughly. Check the outside of the
piston rod (223) and the inside of the cylinder (216) for
0678 0678
scoring or scratches, which prevent the packings
from sealing properly. Replace all worn parts.
C. Alternate polyethylene and leather packings as
shown in Fig 19–1, starting with the polyethylene
packings. Incorrect installation damages the pack-
ings and results in pump leakage. Notice that:
the lips of the throat v–packings face down;
the lips of the piston V–packings face up;
the lips of the U–cup seal (205) face down.
D. Coat the piston rod and the inside of the cylinder with
lightweight oil, and soak the packings in oil before
reassembling.
WARNING