Skytrak 6042 Service Manual User Manual download pdf (Page 343)

8.111

Model 6042 Legacy Origin 7/02

Hydraulic System

13. Lubricate the inside of the tube (Fig. 8-73, 2) and

outside of the piston (8) and head gland (7) with

clean, filtered hydraulic oil.

14. Apply a compression sleeve or other suitable tool to

the head gland (Fig. 8-73, 7) and piston (8) in order

to compress the o-rings, back-up rings and seals,

while inserting the assembled piston, rod and head

gland into the tube (2).

IMPORTANT: When sliding the rod (Fig. 8-73, 6) and

piston assembly into the tube, prevent the threaded end

of the tube from damaging the piston (8). Keep the rod

centered within the tube to help prevent binding. Protect

the finish on the rod at all times. Damage to the surface

of the rod can cause seal failure.

15. Carefully insert the rod (Fig. 8-73, 6) with all

attachments straight into the tube (2).

16. Using a pin spanner wrench, thread the head gland

(Fig. 8-73, 7) into the tube (2). Torque the head

gland to 300-400 lb-ft (407-542 Nm).

17. Lubricate the counterbalance valve (Fig. 8-73, 3)

and the pilot-operated check valve (5) with clean,

filtered hydraulic oil. Using new oiled o-rings, thread

the counterbalance valve and the pilot-operated

check valve into the cylinder. Torque the valves to

40-50 lb-ft (54-68 Nm).

IMPORTANT: DO NOT tamper with or attempt to reset

the counterbalance valve cartridge. If adjustment or

replacement is necessary, replace a counterbalance

valve with a new part.

18. Test the cylinder at low operating pressure [100 psi

(7 bar)]. Verify that the piston and the rod move

freely in both directions.

19. Increase the operating pressure to the maximum

amount for the cylinder [3,000 psi (207 bar)], and

again check for free movement in both directions.

20. Retract the rod fully into the tube, and cap and plug

the hydraulic hose ports.

f. Extend/Retract Cylinder Installation

1. Attach a suitable sling to an overhead crane or other

suitable device and to the extend/retract cylinder. Make

sure the device used can actually support the cylinder.

Place the extend/retract cylinder in position guiding the

rod end through the retainer on the outer boom.

Note: Check the condition of the rubber bumper located

on the retainer. Replace if damaged. Refer to Section

3.3.3, “Outer Boom Removal.”

2. Coat the extend/retract cylinder base pin with anti-

seize compound and install the pin by tapping it in.

3. Secure the extend/retract cylinder base pin to the

boom with two 2" external retaining rings.

4. Guide the rod end into position aligning the eye with

the intermediate boom mounting holes. Coat the

extend/retract cylinder rod pin with anti-seize

compound and install the pin by tapping it in.

5. Secure the extend/retract cylinder rod pin to the

boom with two 2" external retaining rings.

6. Connect the extend/retract cylinder hydraulic hoses

in relation to the labels or markings made during

removal.

7. Start the engine and run at approximately one-third to

one-half throttle for about one minute without moving the

vehicle or operating any hydraulic functions.

8. Inspect for leaks and check the level of the hydraulic

fluid in the reservoir. Add hydraulic fluid to the

reservoir as needed. Shut the engine OFF.

9. Wipe up any hydraulic fluid spillage in, on, near and

around the vehicle, work area and tools.

10. Conduct a pressure check of the attachment tilt

cylinder hydraulic circuit and bleed the circuit as

outlined in the procedure that follows.

g. Extend/Retract Cylinder Pressure Checking and

Circuit Bleeding

1. Attach a 4,000 psi (276 bar) gauge to the test fitting

on the “VG” port of the unloader valve to test the

system pressure. Pressure readings should be

3,000 ±100 psi (207 ±7 bar). Refer to Section 8.7,

“Hydraulic System Testing.” To check the cylinder

pressure, consult the factory.

2. With no accessory installed on the Quick Attach,

start with the lift/lower and attachment tilt cylinders

fully retracted.

3. Fully extend the extend/retract cylinder. Hold the

joystick at full extend while fully raising the lift/lower

cylinder.

4. Fully retract the attachment tilt cylinder. Hold the

attachment tilt joystick at full retract while fully

retracting the lift/lower cylinder.

5. Repeat Steps 3-4 five times.

WARNING: Avoid prolonged engine

operation in closed areas with inadequate

ventilation. Failure to properly ventilate exhaust

fumes can result in death or serious injury.

WARNING: Escaping hydraulic fluid

under pressure can penetrate the skin, causing

death or serious injury.

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Skytrak 6042 Service Manual User Manual Page 343

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Skytrak 6042 Service Manual User Manual Page 343

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