JLG 340AJ Service Manual - Manual (Page 73)

SECTION 3 - CHASSIS & TURNTABLE
3121259 – JLG Lift – 3-33
Table 3-3. Swing Motor Troubleshooting
Trouble Cause Remedy
Oil Leakage 1. Hose fittings loose, worn or damaged.
2. Oil seal rings (4) deteriorated by excess heat.
3. Special bolt (1, 1 A, 1B or 1C) loose or its sealing area deterio-
rated by corrosion.
4. Internal shaft seal (16) worn or damaged.
5. Worn coupling shaft (12) and internal seal (16).
Check & replace damaged fittings or "O" Rings. Torque to manufac-
turers specifications.
Replace oil seal rings by disassembling unit.
(a) Loosen then tighten single bolt to torque specification.
(b) Replace bolt.
Replace seal. Disassembly of motor unit necessary.
Replace coupling shaft and seal by disassembling unit.
Significant loss of speed under load 1. Lack of sufficient oil supply
2. High internal motor leakage
3. Severely worn or damaged internal splines.
4. Excessive heat.
(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.
Replace worn rotor set by disassembling unit.
Replace rotor set, drive link and coupling shaft by disassembling
unit.
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
2. Internal interference
3. Lack of pumping pressure
4. Excessive binding or loading in system external to motor unit.
Locate blockage source and repair or replace.
Disassemble unit, identify and remedy cause and repair, replacing
parts as necessary.
Check for and repair worn pump.
Locate source and eliminate cause.