2–3 HYDRAULIC CONTROL VALVE
IMPORTANT
When making repairs on hydraulic system, clean the work area before disassembly and keep all parts clean. Always use caps and plus on hoses, tbelines and ports to keepdirt out. Dirt can quickly damage the system. I–2056–0793
Wear in the control valve or spools will cause the hydraulic cylinders to move when the controls are in the neutral position. W ear can also cause loss of hydraulic power. To find an internal leak in the control valve, first check the condition of the cylinders. If the lift arm or tilt cylinder still move or extend after the cylinders are checked to be good, then check the control valve for the following: 1. Spool not centering in the valve section when the pedal is released. The spring can be broken or check the pedal linkage and adjust it so it will keep the spool in the neutral position. 2. Check for leaks in the valve because of wear or cracked valve body.
WARNING
Never work on a machine with the lift arms up unless the lift arms are secured by an approved lift arm support device. Failure to use an approved lift arm support device can allow the lift arms or attachment to fall and cause injury or death. W–2059–0598
The tools listed will be needed to do the following procedure: MEL–1003 – Hydraulic Tester MEL–1006 – Hydraulic Test Kit
WARNING
Loader must be restrained for some service and repair. When balance of loader is changed by removal of lift arms or engine, or when it is necessary to rotate axles, jackstands should be put under both front axles and both rear corners of frame. Blocks by wheels can be climbed and do not stop loader.
Dealer Copy -- Not for Resale
2–3.1 Relief Valve
W–2310–0398
Checking the Relief Valve 1. Operate the loader until the fluid is at operating temperature. 2. Stop the engine. 3. Activate the auxiliary hydraulic control (right steering lever) to raise the hydraulic pressure.
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Revised Oct. 98
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540, 543 Loader Service Manual
