10
306–646
Model 222–638 Displacement Pump
(Used on Models 222–526, 222–539, 223–984
and 223–991)
NOTE:
Before beginning, read “Before Y ou Start” on
page 8.
Disassembly
NOTE:
Refer to Fig 3 and the parts drawing during the
following procedure.
1. Remove the cotter pin (41). Unscrew the coupling
nut (50) and the three tie rod locknuts (44). Pull the
displacement pump (2) off the air motor (1).
2. Remove the cotter pin (42). Loosen the locknut (45).
Unscrew the connecting rod (53) from the displace-
ment rod (60).
3. Insert a 1/4 in. (6 mm) diameter rod in the holes of the
packing nut/wet–cup (21), and loosen it. Push the
displacement rod (60) down until the priming piston
(37) clears the intake valve housing (28). Remove
the nut (6), priming piston (37), valve plate (36) and
plate guide (31).
4. Unscrew the four tie bolts (8) and pull the intake valve
housing (28) off the pump. Pull the priming rod (62)
and displacement rod (60) out of the bottom of the
cylinder (59). Remove the pin (7) and unscrew the
priming rod (62) from the adapter (61).
5. Pull the cylinder (59) down out of the outlet housing
(26). Inspect the inner surface of the cylinder and the
outer surface of the displacement rod (18) for
scratches or scoring, which can cause premature
packing wear and leaking. To check, run a finger over
the surface or hold the part up to the light at an angle.
6. Disassemble the intake valve (3). Clean and inspect
all parts, replacing as necessary . Check the intake
valve seat (30) for nicks or damage.
7. Unscrew the adapter (61) from the displacement rod
(60). Remove and inspect the piston (38). Disas-
semble the piston.
8. Unscrew the packing nut/wet–cup (21). Remove the
wiper seal (66). Remove the throat packings from the
outlet housing (26).
9. Clean and inspect all parts, replacing as necessary.
Reassembly
NOTE:
Refer to Fig 3 and the parts drawing during the
following procedure.
1. See Detail A of Fig 3. The gland/packing stack (64*)
for the throat is preassembled.
Do not disassemble
the stack.
Lubricate the gland/packing stack and in-
stall it into the outlet housing (26).
Be sure the lips of
the v–packings are facing down. Install the wiper
seal (66) in the groove of the wet–cup (21)
with the
lips facing down. Loosely install the packing nut/wet–
cup (21).
2. See Detail B of Fig 3. Install the two bearings (35*)
and the u–cup packing (56*) on the piston (38).
Be
sure the lips of the packing are facing up.
3. Install the piston (38), valve plate (34), and adapter
(61) on the displacement rod (60).
4. Thread the connecting rod (62) into the adapter (61)
and secure with the pin (7).
5. Install one copper gasket (27*) in the outlet housing
(26). Push the displacement rod (60) and priming rod
(62) up into the outlet housing (26) so the top of the
displacement rod just protrudes from the packing
nut/wet–cup (21). Lubricate the priming rod (62).
6. Install the cylinder (59) in the outlet housing (26), be-
ing careful not to scratch the polished inner surface
of the cylinder.
7. See Detail C of Fig 3. Slide the intake valve gland/
packing stack (65*) into the intake valve seal housing
(3).
Do not disassemble the stack.
Be sure the lips
of the v–packings are facing up. Tighten the packing
nut (11). Install the valve seat (30) in the intake valve
housing (28). Place the intake valve seal housing (3)
on the seat (30).
8. Install two copper gaskets (27*) on the intake valve
stop (29). Install the stop in the intake valve housing
(28).
9. Carefully guide the intake valve housing (28) up over
the priming rod (62) and install it on the cylinder (59).
Insert the four tie bolts (8) through the outlet housing
(26) and engage the holes in the intake valve hous-
ing. Torque the tie bolts oppositely and evenly to 60
ft–lb (82 N.m).
10. Install the plate guide (31), plate (36), priming piston
(37) and nut (6) on the priming rod (62). If necessary,
push down on the displacement rod (60) to provide
sufficient clearance from the intake valve housing
(28).
11. Tighten the packing nut/wet–cup (21) just enough to
prevent leakage – no tighter.
12. Check the alignment of the displacement rod (60) by
inserting a size E (0.254 in. diameter) drill shank be-
tween the packing nut/wet–cup (21) and the rod. If
the drill shank cannot be passed freely around the
rod, tighten the tie bolt (8) on the side which is bind-
ing.
13. Screw the connecting rod (53) into the top of the dis-
placement rod (60). Insert the cotter pin (42) and
tighten the locknut (45).
14. Align the pump outlet on the outlet housing (26) with
the optional outlet at the base of the air motor (1).
Loosely screw the tie rod locknuts (44) onto the tie
rods (52). Lubricate the o–ring (47) and the top
thread of the connecting rod (53). TIghten the cou-
pling nut (50) to attach the displacement pump to the
motor. Insert the cotter pin (41).
15. Start the pump and run it slowly to check for binding.
Adjust the tie rods as necessary , then torque the
locknuts (44) to 40–50 ft–lb (54–68 N.m).
16. Reconnect the fluid and air lines. Reconnect the
ground wire if it was disconnected during service.
