O-Rings; Shaft Seals; Hydraulic Motor Removal & Replacement - Gravely Promaster 100 Service Manual

7. Install the charge relief valve ball and spring. The
charge relief ball goes into the end cap charge hole
pocket first and the spring is installed between the
ball and recess of the charge cover.
8. Install the charge pump gerotor assembly.
9. Install the charge pump cover and O-ring. The
charge relief valve spring must enter the recess in
the cover.
10.Install the charge pump cover screws. Torque the 5
mm screw to 84-100 in-lbs (9.8-13.5 Nm).
11.Rotate the shaft to assure correct assembly. When
properly assembled, minimal torque should be
required to turn the shaft.

12.9 O-RINGS

To replace an O-ring on a check valve plug, remove the
plug and with a small screwdriver or hook, stretch the
O-ring off the plug. Apply clean oil to the new O-ring
and roll it into its groove. While installing the plug, use
care to align the plug stem with the proper core to
avoid damage. Torque plug to
15-35 ft-lbs (20-47 Nm).
To replace an O-ring and a back-up ring on the bypass
valve, remove the valve, and with a small screwdriver
or hook, stretch the O-ring off the valve. The back-up
ring is split and may be removed in the same manner.
Apply clean oil to the new back-up ring and the new O-
ring. Install the new back-up ring prior to installing the
new O-ring. Torque bypass valve to
7-10 ft-lbs (9.4-13.5 Nm).

12.10 SHAFT SEALS

Lip-type seals are used on the input shaft, and
displacement control shaft of the Series 70 pumps.
These seals can be replaced without major
disassembly of the unit. However, replacement of the
seals generally requires removal of the pump from the
machine.
Figure 29 - Input Shaft Seal Removal
1. To replace the pump input shaft seal, first remove
the retaining ring from the housing.
2. Carefully pull the seal out of the housing bore. A
hook-type tool may be used to grasp the seal and
pull it out. A slide hammer-type puller may also be
used to remove the seal. Care must be taken so as
not to damage the housing bore, shaft sealing
surface, or bearing. Once removed the seal is not
reusable.
3. Inspect the sealing area on the shaft for rust, wear,
or contamination. Polish the sealing area on the
shaft if necessary. Lubricate the new seal with
clean oil.
4. Wrap the spline or key end of the shaft with thin
plastic to prevent damage to the seal lip during
installation. Slide the seal over the shaft and press
it into the housing bore. Be careful not to damage
the seal.
5. Install the seal retaining ring in the housing.
6. The displacement control shaft seals may be
replaced by following a similar procedure. These
seals are not held in position by a retaining ring.
Press in flush to bottom of bore.
7. Reverse the disassembly procedure to
reassemble.
8. Check that there is no binding of speed control
linkage when assembled.
9. Adjust the drive belt tension by turning the two nuts
on the idler rod until the correct air cap of
approximately 0.010 inches (0.25 mm) is obtained.
Lock the two jam nuts together.
10.Grease the flanged support bushing.
11.Refer to Filter Change and Run-In Procedure.
12.11 HYDRAULIC MOTOR REMOVAL &
REPLACEMENT
1. Refer to Wheel and Hub Removal.
2. Place an open-top container under the motor and
clean the two hose fittings prior to removing the
hydraulic hoses.
3. Disconnect the two hydraulic hoses, cap hoses,
and motor inlet parts to prevent contamination.
4. Loosen the four bolts holding the hydraulic motor.
Be sure to support the hydraulic motor when
removing the bolts to prevent it from falling out and
causing damage.
NOTE: There is no rebuild kit available for the hydrau-
lic motor. Replacement of the motor is necessary if it is
damaged.
5. Inspect and replace any worn or damaged parts.
6. Reverse the disassembly procedure to
reassemble.
7. Refer to Wheel and Hub Installation.
8. Refer to Filter Change and Run-In Procedure
sections.
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