308793 29
Service
Reassembling the Displacement Pump
NOTE: When thread sealant is specified, use low
strength (blue) Loctiter.
1. Place the halves of the piston (16) around the
packing (15*) and snap them together. See Fig.
15.
2. Apply thread sealant to the piston rod (17) threads.
Screw the rod through the piston and packings and
into the special piston nut (12). Torque the nut to
68–81 NSm (50–60 ft-lb).
3. With the lower pump housing (11) turned upside
down, install the balls (5) and the gaskets (7*).
WARNING
COMPONENT RUPTURE HAZARD
The relief valve seat (6) must be in-
stalled at the fluid intake, as shown in
Fig. 15. The relief valve relieves pres-
sure trapped in the pump cylinder when the pump
is shut off, and reduces the risk of pump overpres-
surization. The seat cannot relieve pressure if
installed in any other position.
4. Install the relief valve intake seat (6) in the left side
of the lower housing (11), as viewed in Fig. 15 (the
arrow on label 35 points to the correct location).
The pin (P) on the seat must point up into the
housing. The pin limits the positioning of the seat,
ensuring that the vent hole (V) is not blocked by
part of the housing. Refer to Fig. 14.
5. Install the intake seat without a relief valve (34) in
the right side of the lower housing (11).
NOTE: The seats (6 and 34) are not reversible; the
chamfered side must face the ball.
Fig. 14
7523B
6
V
7*
11
10
P
6. Place the intake housing (10) on the lower pump
housing (11). Install the lockwashers (8) and
capscrews (9). Torque to 34–40 NSm (25–30 ft-lb).
See Fig. 15.
7. Place the intake housing (10) in a vise. Place one
o-ring (2*) in each side of the lower pump housing
(11), where the tubes (3) sit. Place o-rings (2*) in
the grooves at each end of the tubes. Place a
gasket (18*) in both the upper and lower housings
(1 and 11). Position the tubes and cylinder (4) in
the lower housing (11).
8. Lubricate the inside of the cylinder (4). Slide the
piston assembly into the cylinder.
9. On stainless steel pumps, install the o-ring (39{)
on the throat cartridge (38), then screw the throat
cartridge into the upper pump housing (1).
10. Lubricate the throat packings and glands. Install
one male gland (19{), then five v-packings with the
lips facing down: one UHMWPE (20{), one leather
(25{), UHMWPE, leather, UHMWPE. Install the
female gland (26{). Install three v-packings with
the lips facing up: UHMWPE, leather, UHMWPE.
Install the other male gland (19{). Install the
packing nut (21) finger-tight.
NOTE: Model 239859, 239860, 240612, and 240613
displacement pumps use 8 v-packings (20) in
the throat, instead of 5 UHMWPE (20) and 3 leather
(25) as on all other models.
11. Install the upper pump housing (1). It may not seat
well on the tubes and cylinder. Install the bolts and
lockwashers (14) from the lower pump housing
(11). As you tighten the bolts into the upper hous-
ing (1), they will draw the housings firmly onto the
tubes and cylinders. Tighten the bolts uniformly
and torque to 34–40 NSm (25–30 ft-lb).
12. On stainless steel pumps, torque the cartridge
(38) to 135 NSm (100 ft-lb).
13. Torque the packing nut (21) to 34–40 NSm (25–30
ft-lb).
14. Place a ball (23), seat (24) and gasket (7*) in each
side of the outlet housing (22). Install the outlet
housing on the upper pump housing (1). Note that
the flatter side of the housing faces the outside
edge of the pump. Install the lockwashers (8) and
screws (9), and torque to 34–40 NSm (25–30 ft-lb).
15. Reconnect the displacement pump to the motor as
explained on page 22.
