Pump And Motor Rotor Inspection - Gravely Promaster 300 Service Manual

Turn the cover assembly back over and using a
No. 5 or 7 internal retaining ring pliers, remove the
input shaft retaining ring.
9. Reposition and support the cover allowing room for
shaft removal. With the input shaft in the down
position, use a plastic head hammer or press to
remove the input shaft assembly from the cover.
No further disassembly of the shaft and bearing
assembly is required as they are serviced as an
assembly.
10.Using a screwdriver or similar tool, drive the input
shaft seal from the cover.
11.To remove the control shaft seal, reposition the
cover. Using a small screwdriver or similar tool, pry
the control shaft seal from the cover.
12.Remove the cover gasket from the housing.
NOTE: The gasket may have remained on the cover.
13.Remove the drive from the pump rotor assembly.
14.Remove the charge pressure relief valve spring
from the housing (see Figure 28).
Figure 28
15.Using a pencil, magnet, or similar tool, remove the
charge pressure relief ball from its seat in the
housing.
16.Remove the control shaft and insert from the
housing and cam ring assembly.
17.Remove the cam ring insert from the control shaft.
18.Remove the cam ring assembly from the housing.
19.Carefully remove the pump rotor assembly from
the housing, making sure the ball pistons are not
dislodged from their bores.
IMPORTANT: It is essential that the pump rotor
assembly remain intact during handling as each ball
piston is matched to its respective bore.
20.Install a wide rubber band around the pump rotor
to retain the ball pistons in their bores (see
Figure 29).
9.5 PUMP AND MOTOR ROTOR
INSPECTION
Disassemble and inspect the rotor assembly as
follows:
1. Remove the piston balls from the rotor, one at a
time, working clockwise from the letter stamped in
the rotor face.
2. Place the piston balls in a prepared container. Use
a container such as an egg carton or ice cube tray
to hold the balls.
NOTE: The balls must be placed in the same bores
from which they were removed because they are all
select fit.
3. Check for broken or collapsed springs in the motor
rotor. When broken or collapsed springs are found
with no other irregularities, the springs may be
replaced individually without replacing the
complete motor rotor assembly.
4. Inspect the piston balls. They must be smooth and
completely free of any irregularities.
5. Inspect the rotor bores, rotor bushing, and pintle
journals for irregularities or excessive clearance.
the ball piston to rotor bore clearance is select fit
electronically from 0.0002" (0.005 mm) to 0.0006"
(0.015 mm). When irregularities are noted, replace
the complete rotor assembly.
6. Install the ball pistons in their matching bores. Hold
them in place with a rubber band or separate race.
9 - 27
Figure 29