Hoist System Troubleshooting
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Illustration 1 | g02321053 |
(1) Hoist pump
(2) Outlet side (3) Inlet side |
Performance tests can be used for diagnosing poor performance and for finding the source of oil leakage inside the hydraulic system.
Probable Cause
- The low-pressure relief valve in the hoist control valve opens at low oil pressure.
- The high-pressure relief valve in the hoist control valve opens at low oil pressure.
- There is a loose connection in the oil line on inlet side (3) of hoist pump (1).
- The hoist pump (1) is excessively worn.
Problem: The temperature of the oil is too hot.
Probable Causes
- The viscosity of the oil is incorrect.
- The low-pressure relief valve in the hoist control valve opens at low oil pressure.
- The high-pressure relief valve in the hoist control valve opens at low oil pressure.
- The hoist pump (1) is excessively worn.
- There is a restriction in an oil passage.
- The load on the system is too high.
Problem: The output of the hoist pump is too low.
Probable Cause
- The oil level of the hydraulic tank is too low.
- The viscosity of the oil is incorrect.
- The hoist pump (1) is excessively worn.
Problem: The pressure of the oil is too low.
Probable Cause
- The low-pressure relief valve in the hoist control valve opens at low oil pressure.
- The high-pressure relief valve in the hoist control valve opens at low oil pressure.
- The hoist pump (1) is excessively worn.
- An O-ring seal failed in the hydraulic system.
Problem: The body will not lower.
Probable Cause
- There is a problem with the engine speed sensor that is located on the flywheel housing.
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