HY13-1597-01/US
3Z Motor Service Procedure
3ZG Series
Parker Hannifin Corporation
Hydraulic Pump & Motor Division
Greeneville, TN 37745 US
6
Trouble
Cause
Remedy
Oil Leakage
1. Hose fittings loose, worn or
damaged.
Check & replace damaged
fittings or “O” Rings. Torque to
manufacturers specifications
2. Oil seal rings (4) deteriorated by
excess heat.
Replace oil seal rings by
disassembling 3Z unit
3. Special bolt (1, 1A, 1B or
1C) loose or its sealing area
deteriorated by corrosion.
(a) Loosen then tighten single bolt
to torque specification.
(b) Replace bolt.
4. Internal shaft seal (16) worn or
damaged.
Replace seal. Disassembly of 3Z
unit necessary.
Significant loss of speed
under load
1. Lack of sufficient oil supply
(a) Check for faulty relief valve and
adjust or replace as required.
(b) Check for and repair worn
pump.
(c) Check for and use correct oil for
temperature of operation.
2. Excessive heat.
Locate excessive heat source
(usually a restriction) in the system
and correct the condition.
Low mechanical efficiency or
undue high pressure required to
operate unit
1. Line blockage
Locate blockage source and repair
or replace.
2. Internal interference
Disassemble 3Z unit, identify and
remedy cause and repair, replacing
parts as necessary
3. Lack of pumping pressure
Check for and repair worn pump.
4. Excessive binding or loading in
system external to 3Z unit.
Locate source and eliminate cause
CAUTION: If the hydraulic system fluid becomes overheated [in excess of 200°F (93.3°C)], seals in the
system can shrink, harden or crack, thus losing their sealing ability.
Troubleshooting Checklist
