SkyTrak 8042 Service Manual - Manual (Page 173)

8-29 6036, 6042, 8042, 10042, 10054
Hydraulic System
6. Start the engine and run at approximately 1/3-1/2
throttle for about one minute without moving the
machine or operating any hydraulic functions.
7. Inspect for leaks and check the level of the hydraulic
fluid in the reservoir. Shut the engine OFF.
Note: Check for leaks and repair as required before
continuing. Add hydraulic fluid to the reservoir as
needed.
8. Wipe up any hydraulic fluid spillage in, on, near and
around the machine, work area and tools.
9. Install the transmission covers.
10. Close and secure the rear door.
d. Steering Test
Refer to Section 8.4.1, “Hydraulic Pressures.”
1. Conduct a pressure check of the steering hydraulic
circuit.
2. Check each steering mode for proper function.
8.7.7 Unloader Valve (6036 & 6042 only)
The unloader valve (1) creates system pressure and
distributes the hydraulic fluid for various machine
functions via its load sense, by to tank (via the oil cooler),
and primary and secondary valve ports. The unloader
valve is secured to the frame toward the front of the
machine near the main control valve.
a. Unloader Valve Removal
1. Park the machine on a firm, level surface, level the
machine, fully retract the boom, raise the boom, place
the transmission control lever in (N) NEUTRAL,
engage the park brake and shut the engine OFF.
2. Place a Do Not Operate Tag on both the ignition key
switch and the steering wheel, stating that the
machine should not be operated.
3. Temporarily block up or support the raised boom.
4. Open the rear door. Allow the system fluids to cool.
5. Properly disconnect the battery.
6. Label, disconnect and cap the hydraulic hoses
attached to the unloader valve. Cap all fittings to
prevent dirt and debris from entering the hydraulic
system.
7. Remove the hardware securing the unloader valve
to the machine frame.
8. Remove the unloader valve.
b. Unloader Valve Disassembly
DO NOT loosen, disassemble or attempt to adjust any
cartridges unless specifically instructed by the
manufacturer. Tampering with the cartridges will
irrevocably alter pressure in the affected circuits.
c. Unloader Valve Installation
1. Place the unloader valve in its original orientation on
the machine frame and secure with the previously
used hardware. Torque capscrews to 31 lb-ft
(42 Nm).
2. Uncap and connect the previously labeled hydraulic
hoses to their appropriate locations.
Note: ALWAYS replace seals, o-rings, gaskets, etc.,
with new parts to help ensure proper sealing and
operation. Lubricate seals and o-rings with clean
hydraulic oil.
3. Check the routing of all hoses, wiring and tubing for
sharp bends or interference with any rotating
members.
4. Properly connect the battery.
5. Remove the Do Not Operate Tags from both the
ignition key switch and the steering wheel.
6. Start the engine and run at approximately 1/3-1/2
throttle for about one minute without moving the
machine or operating any hydraulic functions.
7. Inspect for leaks and check the level of the hydraulic
fluid in the reservoir. Shut the engine OFF.
Note: Check for leaks and repair as required before
continuing. Add hydraulic fluid to the reservoir as
needed.
8. Wipe up any hydraulic fluid spillage in, on, near and
around the machine, work area and tools.
MA8391
1