7E
DISASSEMBLING AND REPAIRING THE PISTON PUMP
1) Remove the cotter pin and pump handle. With the pump facing towards you
lay the unit on its back (Figure 1). Loosen the hose clamp and remove the
sprayer hose. Caution: There could be residual liquid in the hose and pressure
cylinder. Remove the nut and bolt from the protective cap and remove the cap
(ref: figure 9). Rotate the pump shaft in order to reach two lever bolts(A). Using
an allen wrench, remove the lever bolts. Pull the piston assembly (B) out of the
piston cylinder (C).
2) Remove the piston cylinder assembly by turning the piston cylinder
counter-clockwise when viewing the sprayer from the bottom. Caution: The
piston cylinder may have sharp edges.
3) Check for vertical scratches on the inside of the piston
cylinder and the piston. If one or both are scratched replace
them.
4) To replace the collar, push it off of the crown of the
piston with your thumb. You will see form fitted slots
to install the new collar on to the piston crown.
6) Grease the 2 O-rings on the piston cylinder (do not get any grease on the
valve plate) and screw the piston assembly into the pressure cylinder base.
Screw the piston cylinder clockwise until tight and the bottom O-ring is no
longer visible. When properly placed, the tab on the piston cylinder will line up
with the rib on the pressure cylinder base.
5) There are 2 valve plates on the piston cylinder, one on the inside of
the cylinder and one on the outside top. The valve plates are held in
place with a screw and washer and can be removed and replaced using a
Phillipshead screw driver. The 2 o-rings can be removed and replaced as
well. Insure that the o-rings are positioned in the o-ring grooves in the
piston cylinder.
Figure 1
Figure 6
Figure 2
Figure 3
Figure 4
Figure 5
C
B
A
Collar
Piston
Cylinder
Intake
Upper
Valve
Plate
Lower
Valve Plate
Outlet
Passage
Pressure cylinder
base rib
Piston cylinder tab
