17
820-007
Displacement Pump
3.
Unscrew and remove the packing nut (38). Using a
rubber mallet, tap the piston rod (47) down and
pull it out through the bottom of the cylinder (46).
See Fig. 8 and 9.
4.
Remove the glands (34 & 37) and the packings (35
& 36).
5.
Clean and inspect the piston rod and the inside of
the cylinder for nicks, scratches or scoring which
could cause leaking or premature wear of the
packings.
6.
Clamp the flats of the piston rod in a vise. Use a
wrench to loosen the nut (33) and unscrew the pis-
ton valve (49) from the piston rod. Remove the ball
(27), nut (33), glands (30 & 32), packings (31 &
43), seal (29), and washer (45).
Assembling the Pump
1.
When assembling the pump, coat the packings,
the piston rod and the inside of the cylinder with
oil.
2.
When reassembling the piston, install the new
glands and packings in the correct order, alternat-
ing the leather and plastic packings. See Fig. 8.
The “V” of the packings must face up against the
fluid pressure. See Fig. 9. Tighten the nut (33) to
10.5 in–lb (1.2 N.m) to seat the packings, then
back off the nut and hand tighten it.
3.
Place a new ball (27) in the piston rod (47). Apply
locking compound to the threads of the piston
valve (49) and screw it into the rod hand tight, 1–2
in–lbs (0.11–0.22 N.m) torque. Tighten the nut
against the piston rod to 18–20 ft–lb (24–27 N.m)
torque, without changing the tightness of the nut
against the packings.
4.
Install the throat packings, glands and packing nut,
leaving the packing nut loose. The “V” of the pack-
ings must face down against the fluid pressure.
Alternate the plastic packings (36) and the leather
packings (35). See Fig. 8.
5.
Insert the piston rod (47) through the bottom of the
pump cylinder (46).
6.
Assemble and install the intake valve (48); torque
it to 75–85 ft–lb (100–115 N.m). Tighten the pack-
ing nut (38) just enough to stop leakage––no tight-
er.
3
Fig. 8
38
37
36
35
34
46
47
27
33
32
43
31
30
29
45
49
Fig. 9
0743
0700
48
46
47
38
4
5
Torque to 18–20 ft–lb
(24–27 N.m)
Torque to 1–2 in–lb
(0.11–0.22 N.m)
4
5
1
3
6
2
V of packing faces down
V of packing faces up
U–cup packing faces down
Torque to 75–85 in–lb
(100–115 N.m)
1
2
6
1
1
2
2
3
Summary of Contents for 820-001
Page 3: ...3 820 007 Notes...
