SkyTrak 6042 Service Manual - Manual (Page 255)

8.23 Model 6042 Legacy Origin 7/02
Hydraulic System
NOTE:
When checking pressures in
circuits, refer to Section 8.7,
“Hydraulic System Testing” for
correct pressure readings.
Before troubleshooting any
hydraulic circuit, ALWAYS
begin by checking the
following:
1. Hydraulic oil level in the
reservoir
2. All hoses, tubes, fittings
for leaks, kinks,
interference, etc.
3. Air in the lines
Not
OK
If OK
Repair/replace cable
connections. Ensure lift/lower
section of main control valve is
functioning.
Not
OK
Check main relief pressure at
“VG” port of unloader valve.
Adjust/repair/replace relief
valve on unloader valve.
If OK
Not
OK
Check pump flow. Repair/replace pump.
Not
OK
Check packing on
lift/lower cylinder(s).
Repair/replace
lift/lower cylinder(s).
If OK
If the lift/lower cylinders do
not lower, check the cable
connections at the main
control valve.
NOTE:
Refer to Section 2.5.4,
“Performance Specifications” for
approximate cylinder cycle
times. The operation of the
system function should
approximate the times listed.
Not
OK
If the lift/lower cylinders drift
or react slowly, check the
counterbalance and pilot-
operated check valves on
lift/lower cylinder(s).
Replace counterbalance and/
or pilot-operated check valves
on lift/lower cylinder(s).
Not
OK
Check each
lift/lower cylinder packing.
Repair/replace
lift/lower cylinder(s).
If OK
Not
OK
Check the pilot-operated
check the valve on the lift/
lower cylinder(s).
Repair/replace pump.