The M-Series models use a seal ring on the
end of the power piston. A new seal is
installed by placing the back-up O-ring in the
piston groove and installing the square cut
seal ring over it (Figure 120).
The seal material will stretch as it is fitted to
the ring groove. If you let the piston sit with
the seal rings in place it will become easier to
install it in the piston bore. Use of a ring com-
pressor is advised to limit damage to the pis-
Install a new sector shaft seal in the housing
When installing the sector shaft seals, insure
the lip of the seal is toward the housing. The
blue side of the seal is toward you.
The housing will have a beveled chamfer on
one end of the piston housing only. The pis-
ton will be installed through that end of the
At this time, you can reassemble the gear.
Before installation of the piston into the pis-
ton bore of the housing, check for burrs on
either the piston or piston bore. If burrs are
present, they may be removed by polishing
with a fine hand stone or crocus cloth.
Coat both the piston and piston bore of the
housing with a light coat of motor oil.
Carefully insert the piston into the piston
bore of the housing, keeping the ball guide
cavity exposed as shown (Figure 122).
Care must be taken when installing the piston in the housing. Close tolerances may cause
the piston to jam in the housing bore. Any attempt to force the piston at that time could
cause nicking or gouging of the housing bore.