Service
Displacement Pump Repair
NOTE: Repair Kits are available. See page 6. For
the best results, use all the new parts in the kit, even if
the old ones look good. Eight shims (14*) are included
in the kit, but use only the number required. An aster-
isk behind a reference number, for example (3*), indi-
cates that this part is included in the repair kit.
1. Solvent flush the pump, if possible. Follow the
Pressure Relief Procedure on page 2, stopping
the pump at the bottom of its stroke. Then discon-
nect all hoses from the pump.
2. Unscrew the displacement rod (1) from the air mo-
tor connecting rod.
3. Screw the intake valve housing (24) out of the cyl-
inder (11). See Fig. 1. Disassemble and clean the
parts of the valve, inspecting for damage or wear.
If the seat in the valve housing is chipped or worn,
replace the housing (24).
4. Loosen the packing nut (2). Push down on the dis-
placement rod (1) until you can grasp the piston
stud (20). Pull the displacement rod out the bottom
of the cylinder (11).
5. Inspect the outer surface of the displacement rod
(1) and the polished inner surface of the cylinder
sleeve (12) for scoring or wear by running a finger
over the surface or holding up to a light at an an-
gle. Damage to these parts may cause premature
packing wear or leaking. If either is worn or
scratched, replace it.
NOTE: If replacing the sleeve (12), be sure to install it
with the notched end up, and replace the o-ring (10*)
in the notch. If the old sleeve is hard to remove, con-
tact Graco Technical Assistance (see back page).
6. Unscrew the piston stud (20) from the displace-
ment rod (1). Remove the ball (13), shims (14),
backup washers (15), glands (16 and 19), and v-
packings (17 and 18). Clean all parts and inspect
for damage. If the seat on the piston stud (20) is
nicked or worn, replace it.
7. Remove the packing nut/wet-cup (2). Remove the
bearing (3), glands (4 and 7), and v-packings (5
and 6) from the throat of the pump cylinder (11).
Clean all parts and inspect for damage.
8. Lubricate all packings before reassembling the
pump.
9. One at a time, place a male gland (7*), one
UHMWPE v-packing (5*), two
v-packings
(6*), one UHMWPE v-packing (5*), a female gland
(4*), and the bearing (3*) in the throat of the cylin-
der (11).
Be sure the lips of the v-packings face
down in the throat. See Fig. 1.
Fig 1
1
3
4
2
2
3*
5*
*4
11
12
*10
1
13*
16*
17*
18*
17*
19*
15
15
20
30
24
*22
21
23*
Torque to 50–60 ft–lb
(70–80 N.m).
Lips of v-packings
must face down.
Add shims (14*) re-
quired to make
stack height
0.950–0.975 in.
(24.13–24.77 mm).
Apply sealant.
Torque to 200 in–lb
(23 N.m).
5
Lips of v-packings
must face up.
6
1
5
2
3
4
1
5
5
6
02404
*14
6
*7
5*
4
6*
4
PTFE
