SECTION 4 - HYDRAULICS
3121642 – JLG Lift – 4-3
Right Side Wheel Test
1. Place a 4 inch (10.16 cm) high block with ascension
ramp in front of right wheel of the oscillating axle.
2. From platform control station, select LOW drive speed.
3. Set the DRIVE control switch into position and carefully
drive the machine up ascension ramp until right oscillat-
ing axle wheel is on top of block.
4. Verify the axle oscillates to maintain contact with the
ground/ramp. (All four wheels on the ground).
5. Raise machine platform above stowed position approxi-
mately 9 ft (2.7 m) on the 3394RT or 10 ft (3.1 m) on the
4394RT.
6. Carefully drive the machine back off the block and ramp.
7. Have an assistant check to see that the right oscillating
axle wheel that was on the block is in position on the
ground. The axle should oscillate so that all four wheels
maintain contact with the ground.
8. In the current position (platform raised and all four tires
on flat and level surface), carefully drive machine up the
ramp block again.
4.5 CYLINDER REPAIR
NOTE: The following are general procedures that apply to all cyl-
inders on this machine. Procedures that apply to a specific
cylinder will be so noted.
Disassembly
DISASSEMBLY OF THE CYLINDER SHOULD BE PERFORMED ON A CLEAN WORK
SURFACE IN A DIRT FREE WORK AREA.
1. Connect a suitable auxiliary hydraulic power source to
the cylinder port block fitting.
DO NOT FULLY EXTEND CYLINDER TO THE END OF STROKE. RETRACT CYLINDER
SLIGHTLY TO AVOID TRAPPING PRESSURE.
2. Operate the hydraulic power source and extend the cyl-
inder. Shut down and disconnect the power source.
Adequately support the cylinder rod, if applicable.
3. If applicable, remove the cartridge-type holding valve
and fittings from the cylinder port block. Discard o-
rings.
Figure 4-1. Lift Cylinder Holding Valve and Fitting
Removal
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