JLG 450A_AJ Series II Service Manual - Manual (Page 123)

SECTION 3 - CHASSIS & TURNTABLE
3121180 – JLG Lift – 3-73
Table 3-11. 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 deteriorated 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
manufacturers 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 opera-
tion.
Replace worn rotor set by disassembling unit.
Replace rotor set, drive link and coupling shaft by disas-
sembling 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.