Servicing Piston Rod, Upper Check Valve; Servicing Lower Suction Valve - Allpro 400E Operations Manual & Parts List

SERVICING PISTON ROD, UPPER CHECK VALVE

SEE FIG. 13.
1. Disconnect Fluid Pump as per page 18.
2. Place piston in block (PN 331-195) with the 3/8"
dowel pin (PN 331-196) and hold in vise.
NOTE: DO NOT use smaller diameter pin to hold
piston.
3. Place a 7/16" allen wrench into lower piston and
unscrew lower piston from upper piston. Clean all
parts and inspect them carefully for wear and dam-
age. Inspect the surface of piston for wear or damage.
Replace these parts if needed.
4. To reassemble the piston assembly, place in block
using dowel pin and hold in vise. Install O-ring (4),
Seat (3) and Ball (2) and thread upper and lower
pistons together. Slowly hand tighten piston. Ensure
that O-ring (4) and seat (3) , are flush, then torque to
50 Ft.lbs. Do not use locktite on threads.
NOTE: The upper and lower piston must be pur-
chased as an assembly (Item 1, Fig 13). This assem-
bly will not have the ball, seat and O-ring inside.

SERVICING LOWER SUCTION VALVE

1. Unthread suction nut (Item 2, Fig. 21)
and remove suction assembly from
pump body.
2. Remove suction seat assembly,
O-ring, ball and retainer.
3. Clean all parts and inspect them
for wear or damage, replacing parts
as needed.
FIGURE 14
20
FIGURE 13
1
2
3
4
5a
5b
1
FIGURE 13 PARTS LIST
ITEM NO. PART NO. DESCRIPTION
331-093
1
331-027
2
331-026
3
331-100
4
4. If lower seat need replacing, you can
replace the suction seat assembly PN 331-
033A (Lo-Boy) or 331-292 (Hi-Boy)
5. Clean inside of pump body.
6. If no further pump service is needed,
reassemble the lower check valve assembly,
O-ring, ball and retainer in the suction nut and
screw nut onto pump body. Tighten suction
nut with rod tool (189-211).
FIGURE 14 PARTS LIST
ITEM NO. PART NO.
331-011 Pump Body
1
331-029 Retainer
2
331-030 Ball 1/2" Dia.
3
331-032T O-Ring - PTFE
4
331-033A Suction Seat Ass'y (Lo-Boy)
5a
331-292 Suction Seat Ass'y (Hi-Boy)
5b
2
3
4
Piston Ass'y
Ball
Seat
O-Ring-PTFE
DESCRIPTION