Gravely 950001, Maintenance Manual

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6.4 HYDRAULIC PUMP REMOVAL
Hydraulic Pump Servicing
The hydraulic pump should not be touched unless a
problem with the machine operation points to the pump
being the cause of malfunction.
Typical problems could be:
1. Hydraulic oil leaking from bell housing through
pump shaft seal.
2. Slow operation of hydraulic functions.
3. Excessive and rapid heat build-up.
4. Noisy pump operation.
If any of the above symptoms are attributed to the
pump, the pump should be removed, disassembled,
and checked for wear or damage. Excessive wear to
the following components will require replacement of
the pump:
1. Internal surfaces of the pump body. If cut out
exceeds 0.17 mm (0.007”) Replace the pump.
2. The drive shaft if any wear is detectable by touch in
the seal area. Replace the pump if wear exceeds
0.05 mm (0.002”)
3. Any scoring, grooving or burring of the outside
diameter of gear teeth requires replacement of the
pump. Nicking, grooving, or fretting of the teeth
surfaces also necessitates pump replacement.
When the pump is disassembled for inspection the
shaft seal and face seals should be replaced. The fol-
lowing procedure describes shaft seal replacement.
Seal Replacement
Cleaning and seal replacement is the only mainte-
nance that will be carried out on the hydraulic gear
pump. If the matched gear sets or bearing blocks
become damaged or worn, the entire pump must be
replaced. The following procedure describes the
replacement of the shaft seal.
Remove the shaft nut tab washer and woodruff key
from the pump shaft. Using soft jaws place the front
flange in a vice with the shaft pointing down. Mark the
sections with a marker pen. Be sure to align these
marks when reassembling. Use a socket wrench to
remove the 4 hexagon nuts and washers.
IDENTIFICATION OF PUMP PARTS
SHAFT SEAL
FRONT FACE SEAL
WOODRUFF KEY
REAR COVER
PUMP BODY
DOWEL PIN
FRONT FLANGE
TAB WASHER
SHAFT NUT
HEX. NUT & WASHER
TIE BOLTS
GEAR SET
CIRCLIP
FRONT BEARING BLOCK
REAR BEARING BLOCK