Repair
14
334127D
Repair the Piston
The piston valve is available as pre-assembled,
pre-lubricated Kit No. 237906, which includes the piston
seat/guide assembly (P, items 6, 9, 10, 11, and 12).
1. Follow the steps in
Replace the Intake Valve
on
page
12
.
2. Remove the outlet housing (3).
3. Using a rubber mallet, drive the displacement rod
(1) and the priming piston rod (17) out of the cylin-
der (8). Inspect the outer surfaces of the rods for
damage by running a finger over the surface.
4. Remove the seal (6) from the bottom of the cylinder
(8). Shine a light into the cylinder to examine the
inside surface for scoring or damage.
5.
Only if the cylinder is damaged or there is evi-
dence of leaking around the top of the cylinder
(8)
, unscrew the cylinder from the outlet housing
using a pipe wrench. Remove the top cylinder seal.
See Figure 9.
6. Place the flats of the displacement rod (1) in a vise.
Unscrew the piston (9) from the displacement rod;
the priming piston rod (17) comes with it. Slide the
piston seat/guide assembly (10, 11, and 12) off the
piston (9) as shown in Figure 10.
7. Place the piston (9) flats in a vise and unscrew the
rod (17).
8. Place the pre-assembled piston seat/guide assem-
bly (P, items 10, 11, and 12) onto the piston (9) so
the 45 beveled seating surfaces match.
9. Place the flats of the displacement rod (1) in a vise.
Screw the piston (9) onto the displacement rod (1)
hand tight, then torque to 250-265 ft-lb (339-359
N•m).
F
IG
. 8: Remove Piston
F
IG
. 9: Remove Seal
WLD
WLD
F
IG
. 10: Remove Piston Seat/Guide Assembly
F
IG
. 11: Attach Piston to Displacement Rod
WLD
WLD
3
