Lull 944E-42 Service Manual Bedienungsanleitung PDF herunterladen (Seite 154)

Hydraulic System

8-38

944E-42

8.8 HYDRAULIC CYLINDERS

1. Remove any attachment from the machine. Park the

machine on a firm level surface and fully retract the

boom. Allow sufficient work space around the

hydraulic cylinder being removed. Support the boom

if the lift/lower cylinder is being removed. Place the

travel select lever in (N) NEUTRAL, engage the park

brake, shut the engine OFF and chock wheels.

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. Open the rear door. Allow the system fluids to cool.

4. Label, disconnect and cap or plug hydraulic hoses in

relation to the cylinder.

5. Attach a suitable sling to an appropriate lifting device

and to the cylinder. Make sure the device used can

actually support the cylinder.

6. Remove the lock bolt and/or any retaining clips

securing the cylinder pins. Remove the cylinder pins.

7. Remove the cylinder.

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

around the machine, work area and tools.

a. Cylinder Disassembly

1. Clean the cylinder with a suitable cleaner before

disassembly. Remove all dirt, debris and grease

from the cylinder.

2. Clamp the barrel end of the cylinder in a soft-jawed

vise or other acceptable holding equipment if

possible.

Note: Avoid using excessive force when clamping the

cylinder in a vise. Apply only enough force to hold the

cylinder securely. Excessive force can damage the

cylinder tube.

3. If applicable, remove the counterbalance valve from

the side of the cylinder barrel.

Note: DO NOT tamper with or attempt to adjust the

counterbalance valve cartridge. If adjustment or

replacement is necessary, replace the counterbalance

valve with a new part.

4. Extend the rod as required to allow access to the

base of the cylinder.

Note: Protect the finish of the rod at all times. Damage

to the surface of the rod can cause seal failure.

5. Using a pin spanner wrench, unscrew the head

gland from the tube. A considerable amount of force

will be needed to remove the head gland. Carefully

slide the head gland down along the rod toward the

rod eye, away from the cylinder barrel.

Note: When sliding the rod and piston assembly out of

the barrel, prevent the threaded end of the barrel from

damaging the piston. Keep the rod centered within the

barrel to help prevent binding.

6. Carefully pull the rod assembly along with the head

gland out of the cylinder barrel.

7. Fasten the rod eye in a soft-jawed vise, and place a

padded support under and near the threaded end of

the rod to prevent any damage to the rod.

8. Remove the set screw from the piston head.

Note: It may be necessary to apply heat to break the

bond of the sealant between the piston and the rod

before the piston can be removed.

MU6880

WARNING

Significant pressure may be trapped inside the

cylinder. Exercise caution when removing a

counterbalance valve or a pilot-operated check valve

from a cylinder.

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Lull 944E-42 Service Manual Bedienungsanleitung Seite 154

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