Disassembly Procedure
Start By:
- Remove the main control valve. Refer to Disassembly and Assembly, "Bank Valve (Main Hydraulic) - Remove".
| NOTICE |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
Note: Put identification on all lines, on all hoses, on all wires, and on all tubes for installation purposes. Plug all lines, hoses, and tubes. This helps to prevent fluid loss and this helps to keep contaminants from entering the system.
| NOTICE |
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The hydraulic control valve is very sensitive to the presence of dirt or other contaminants. The presence of dirt or contaminants will result in erratic operation or premature failure. Overhaul of the hydraulic control valve in the field is discouraged. The hydraulic control valve should be returned to the Caterpillar dealer for major repairs or overhaul. |
- Remove two screws that attach pressure reducing valve (1) to the main control valve.
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| Illustration 1 | g00452259 |
- Remove pressure reducing valve (1) from the main control valve.
- Remove two bolts and nuts that attach variable pressure valve (2) to the main control valve.
- Remove variable pressure valve (2) from the main control valve.
- Remove two bolts from pressure reducing valve (3) .
Note: This valve is not present on the HH75 Harvester Head. Control of the measuring arm is performed by the eighth valve section in the hydraulic control valve.
Note: Bypass relief valve (4) was removed during removal of the main control valve.
- Remove pressure reducing valve (3) from the main control valve.
- Remove four screws that attach solenoid valve (5) to spool section (6) .
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| Illustration 2 | g00452275 |
- Remove four screws that attach housing (8) to spool section (6) .
- Remove spool assembly (7) from spool section (6) .
- Remove check valve assembly (9) or relief valve assembly (10) from the side of spool section (6) with the solenoid.
Note: Each valve has two holes. The holes will contain either a check valve assembly or a relief valve assembly. The use of a check valve assembly or a relief valve assembly is determined by the function of the valve.
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| Illustration 3 | g00453216 |
- Remove check valve assembly (9) or relief valve assembly (10) from the side of spool section (6) with the housing.
- Repeat step 7 through Step 11 for the remaining valves in the hydraulic control valve.
- Remove nipple (11) and seal ring (12) from the end section of the hydraulic control valve.
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| Illustration 4 | g00452331 |
- Remove through bolts (13) from the hydraulic valve.
- Separate the valves of the hydraulic control valve.
- Remove the O-ring seals from the individual valves.
Note: Clean all parts. Check the condition of all seals and of all components. If any parts are worn or damaged, use new parts for replacements. If the bore in any spool section is worn or damaged, replace that valve.