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SECTION 3 - CHASSIS & TURNTABLE
3.2 OSCILLATING AXLE SYSTEM
The oscillating front axle is attached to the frame by a pivot
pin, which allows all four wheels to remain on the ground
when traveling on rough terrain. The oscillating axle also
incorporates two lockout cylinders connected between the
frame and the axle. The lockout cylinders permit axle oscilla-
tion when the main boom is in Transport Position and when
the boom is oriented between the rear tires as described
under Drive Orientation System. In this system, both of these
boom positions (swing and main boom elevate) are sensed by
two switches. One switch in each position is normally closed
and opens in the unsafe state. The other switch for each posi-
tion is normally open and closes in the safe state.
The lockout cylinders will lock and hold the axle when the
boom is in a position as described above (Main boom above
horizontal or swung beyond the rear tires). The cylinders
unlock when pilot pressure is applied to the holding valves
mounted on the cylinders and lock when pilot pressure is
removed.
Pressure data is relayed to the UGM by a pressure sensing
switch, which commands the function pump to energize until
the switch is closed. When the Main Boom is below horizontal
and swung between the rear tires, the switches provide power
to actuate the two control valves to supply charge pressure to
the lock-out cylinder holding valves. This allows the cylinders
to unlock which allows the axle to float. The first valve is nor-
mally closed and opens when actuated to allow flow to the
lock-out cylinder circuit. The second valve (located between
the first valve and the lock-out cylinders) is normally open to
tank. This valve closes when actuated to block the tank path
and force the flow to the lockout cylinders. If either of these
valves is in its normal state, the axle will be locked. The Ground
Control Module supplies power to and monitors the state of
the boom elevation and oscillating axle switches. If the switch
states do not coincide, the Ground Control Module will
remove power, causing the oscillating axle to lock in the fail
safe position until power is cycled.
The hydraulic pressure and flow is provided by electrical func-
tion pump that only runs as needed to preserve battery power.
3-4
3.3 LOCKOUT CYLINDER BLEEDING
1. Turn ON the machine.
2. Position the turntable to the normal stowed position.
3. Attach clear tubing to bleeder valve nipple.
4. Position a small bucket/bottle in front of the lockout cyl-
inder bleeder valve and insert clear tubing.
5. Using a 3/8" wrench, loosen the bleeder valve, turning
counterclockwise slowly. Bleed air from the top of lock-
out cylinder. Capture hydraulic oil until a steady unbro-
ken stream of hydraulic oil is viewed. Tighten/close the
bleeder valve while stream of hydraulic oil is running.
6. Locate the bleeder valve on the opposite side lockout
cylinder. Repeat the process.
Bleeder Valve
MAE16010
3121634
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Troubleshooting
