Displacement
Pump
4. To disassemble the rest of the pump, remove the
packing
nut (416) and plug (405). See Fig. 43.
5. Use
a plastic mallet to tap the piston rod (424) down.
Pull
the rod out through the bottom of the cylinder
.
6.
Remove the throat packings. See Fig. 43.
WARNING
Always use the special removal tool, P/N 220–991,
to remove the sleeve. Other removal methods
could cause the pump to rupture, resulting in
serious injury
. If the sleeve cannot be removed
easily using the tool, return the sleeve and cylinder
to your Graco distributor for removal.
7. Remove the sleeve. Screw the large nut (B) of the
tool
into
the top of the cylinder (419). Screw down the
rod
(A) to push the sleeve out. Remove the tool. See
Fig.
39.
8. Clamp
the flats of the piston rod (424) in a vise. Loos
-
en
the retaining nut (41
1). Unscrew the piston valve
(422).
See Fig. 40.
9.
Disassemble the piston valve (422). See Fig. 40.
419
B
A
0028
Fig. 39
Reassembly Notes
A. Pump
Repair
Kit, P/N 220–877, is available. For the
best results, use all the new parts in the kit, even if
the
old ones still look good. Parts included in the kit
are
shown
with an asterisk, i.e., (410*) in the text and
drawings.
B. Check
the outside of the piston rod (424) and the in
-
side of the sleeve (418) for scoring or scratches. If
the parts are damaged, new packings will not seal
properly.
Replace these parts if needed.
C Alternate leather and plastic packings as shown in
Fig 31–2. The lips of the throat “V” packings must
face down. The lips of the piston “V” packings must
face
up. The lips of the U–cup seal (403) face down.
Incorrect installation damages the packings and
causes
the pump to leak.
D. Soak
leather packings in oil
before reassembling the
pump.
Reassembly Procedure
1. Stack
the backup washer (414), seal (403*),
female
gland
(415*), alternate the
packings (412*,406*), and
then male gland (410*) onto the piston valve (422).
See
Fig. 40.
2. Tighten
the packing retaining
nut (41
1) onto the pis
-
ton
valve (22) to the torque specified in Fig. 40.
3. Put the ball (425*) on the piston valve (422). See
Fig.
40.
CAUTION
Step 5., tightening the piston valve into the rod, is
critical. Follow the procedure carefully to avoid
damaging the packings by overtightening.
4. Apply
one drop of
adhesive, supplied, to the threads
of the piston valve. Then hand tighten the valve as-
sembly
into the piston rod just
until the nut (41
1) con
-
tacts
the rod. See Fig. 40.
Note the alignment of the piston (422) to the nut
(411). Maintain this alignment through Steps 5., 6.
and
7..
5.
Place the flats at the top of the rod (424) in a vise.
TORQUE
T
O
0.35 N.m
411
422
410*
403*
415*
425*
APPLY ONE DROP
OF SEALANT T
O
THESE THREADS
2 LEA
THER
*406
3
POLY
*412
LIPS F
ACE UP
424
0029
LIPS
F
ACE
DOWN
*414
Fig.
40
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