Troubleshooting - JLG 400S Service And Maintenance Manual

SECTION 3 - CHASSIS & TURNTABLE

Troubleshooting

Item
Check oil level in reservoir and oil Insufficient hydraulic fluid could lead to cavitation that would cause sys-
supply to motor. tem noise.
Check for air in system. Air trapped in system lines or motor could result in cavitation that would
cause system noise.
Inspect output shaft couplings. A loose or incorrect shaft coupling will produce vibrations that could result
in system noise.
Inspect output shaft alignment. Misaligned shafts create excessive frictional vibration that could result in
system noise.
Hydraulic oil viscosity above lim- Viscosity above acceptable limits will result in cavitation that would lead
its. to system noise.
Item
Check oil level in reservoir and oil Insufficient amount of hydraulic fluid will not meet system cooling
supply to pump. demands.
Inspect heat exchanger If heat exchanger fails or becomes obstructed, it may not meet system
(if equipped). cooling demands.
Check system relief valves. If a system relief valve becomes unseated for an extended period of time or
fails for any other reason, the system could become overheated.
Item
Check signal line to servo control Obstructed or restricted flow through the servo control signal lines could
port. result in slow shift or no shift conditions within the motor.
Check correct supply and drain Supply and drain orifices determine motor shift rate. The smaller the ori-
orifices are properly installed fice, the longer time it takes to shift the motor. Obstruction also increases
and not obstructed. shift times.
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Table 3-2. Excessive Noise and/or Vibration
Description
Table 3-3. System Operating Hot
Description
Table 3-4. Won't Shift or Slow to Start
Description
Action
Fill reservoir to proper level and ensure oil supply to motor is adequate and
lines are unobstructed.
Ensure system lines and components are purged of air.
Ensure correct coupling is used and fits properly on shaft.
Ensure that the shafts are properly aligned.
Replace hydraulic oil with appropriate fluid for operating conditions.
Action
Fill reservoir to proper level.
Ensure heat exchanger is receiving adequate air flow and is in good operat-
ing condition. Repair or replace as necessary.
Repair or replace any malfunctioning relief valves and verify loads on
machine are not excessive.
Action
Ensure signal lines are not obstructed or restricted and that signal pressure
is adequate to shift the motor.
Ensure proper control orifices are installed in motor and check they are not
obstructed. Clean or replace as needed.
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