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Personal injury or death can result from sudden machine movement. Sudden movement of the machine or release of air pressure or oil pressure can cause injury to persons on or near the machine. To help prevent possible injury before testing and adjusting any air system or hydraulic system, perform the procedure in the Testing and Adjusting, "General Information" section. |
Perform the visual checks before you troubleshoot a problem. Make sure that the transmission is in neutral and stop the engine. During the visual checks, use a magnet to separate ferrous particles (iron and steel) from nonferrous particles (aluminum, rubber and paper).
Check: Check the oil level in the hydraulic tank.
Check the oil level in the hydraulic tank. Look for air or water in the sight gauge. Add oil to the hydraulic tank, if necessary. See the Operation and Maintenance Manual for the correct type of oil.
Problem: There is an indication of water in the oil.
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| Illustration 1 | g00288130 |
| (1) Rear brake oil coolers | |
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| Illustration 2 | g00288131 |
| (2) Front brake oil cooler | |
Probable Cause
- Failure of either of the rear brake oil coolers (1)
- Failure of the front brake oil cooler (2)
Problem: There is an indication of air in the oil.
Probable Cause
- There is a leakage in the oil lines. See "Check: Check for oil leakage.".
Problem: The oil level is too low.
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| Illustration 3 | g00288132 |
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Final drive plug | |
Probable Cause
- There is a leakage in the oil lines. See "Check: Check for oil leakage.". Add oil before you perform any tests.
- Brake cooling oil can leak into the final drive. Check the oil level in each final drive.
Inspect all oil lines, all hoses and all connections for damage or for leaks. Look for oil on the ground under the machine.
Note: If oil can leak out of a fitting or out of a connection, air can enter the system. Air in the system can be as harmful as having too little oil.
Check: Check the parking brake release hydraulic filter.
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| Illustration 4 | g00519996 |
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(3) Parking brake release hydraulic filter
(4) Bypass switch | |
Remove parking brake release hydraulic filter (3). Inspect parking brake release hydraulic filter (3) for foreign material. Cut the filter open, if necessary.
Note: Parking brake release hydraulic filter (3) has an oil bypass valve. The bypass valve allows the oil to bypass the oil filter element or the screen whenever the pressure difference between the inlet oil and the outlet oil becomes too high. Any oil that does not flow through the filter element or through the screen goes directly into the hydraulic circuit. Dirty oil can cause sticking valves and restrictions in valve orifices. Bypass switch (4) will notify the operator of a restriction.
The pressure setting of the bypass valve in parking brake release hydraulic filter (3) is
Problem: Rubber particles are found.
Probable Cause
- Seal failure
- Hose failure
Problem: Shiny steel particles are found.
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| Illustration 5 | g00288134 |
| (5) Parking brake release pump section | |
Probable Cause
- Mechanical failure of parking brake release pump section (5).
Check: Check the front brake oil cooling filters. Check the screens for the rear brake oil coolers.
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| Illustration 6 | g00288135 |
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Rear brake oil coolers (6) Screens | |
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| Illustration 7 | g00486039 |
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Location of screens | |
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| Illustration 8 | g00288216 |
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Front brake oil cooler (7) Front brake cooling hydraulic filters | |
Remove screens (6) for the rear brake oil coolers. Inspect screens (6). Remove front brake cooling hydraulic filters (7) for the front brake oil coolers. Inspect front brake cooling hydraulic filters (7). Cut the screens and filters open, if necessary.
Note: Front brake cooling hydraulic filter (7) has an oil bypass valve. The bypass valve allows the oil to bypass the oil filter element or the screen whenever the pressure difference between the inlet oil and the outlet oil becomes too high. Any oil that does not flow through the filter element or through the screen goes directly into the hydraulic circuit. Dirty oil can cause sticking valves and restrictions in valve orifices. The bypass switch will notify the operator of a restriction.
The pressure setting of the bypass valve in front brake cooling hydraulic filter (7) is
Problem: Rubber particles are found.
Probable Cause
- Seal failure
- Hose failure
Problem: Shiny steel particles are found in the screens for the rear brake oil coolers.
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| Illustration 9 | g00288217 |
| (8) Brake cooling pump section | |
Probable Cause
- There is a mechanical failure of any brake cooling pump section (8).
Problem: Shiny steel particles are found in the oil filters for the front brake oil coolers.
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| Illustration 10 | g00288134 |
| (5) Parking brake release pump section | |
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| Illustration 11 | g00288218 |
| (9) Hoist and front brake cooling gear pump | |
Probable Cause
- Mechanical failure of the parking brake release pump section (5). Refer to "Check: Check the parking brake release hydraulic filter.".
- Mechanical failure of the hoist and front brake cooling gear pump (9). Refer to "Check: Check the hoist and front brake cooling screens.".
Check: Check the hoist and front brake cooling screens.
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| Illustration 12 | g00520063 |
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Hoist control valve (10) Screens (hoist) | |
Remove screens (10). Inspect screens (10) for foreign material or for restrictions.
Problem: Rubber particles are found.
Probable Cause
- Seal failure
- Hose failure
Problem: Shiny steel particles are found.
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| Illustration 13 | g00288218 |
| (9) Hoist and front brake cooling gear pump | |
Probable Cause
- Mechanical failure of the hoist and front brake cooling gear pump (9).
Check: Check the inside of the hydraulic tank.
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| Illustration 14 | g00288220 |
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Rear of hydraulic tank (11) Tank drain (12) Suction screens (hoist and front brake cooling gear pump sections) (13) Suction screens (rear brake cooling and parking brake release pump sections) (14) Suction screens (rear brake cooling pump sections) | |
Drain the oil from the hydraulic tank at tank drain (11). Inspect the bottom of the hydraulic tank for debris. Remove the hoses from the back of the hydraulic tank in order to remove suction screens (12), (13) and (14) and clean the suction screens.
| 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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products. Dispose of all fluids according to local regulations and mandates. |
Problem: Rubber particles are found.
Probable Cause
- Seal failure
- Hose failure
Problem: Shiny steel particles are found.
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| Illustration 15 | g00288221 |
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(5) Parking brake release pump section
(8) Brake cooling pump section (9) Hoist and front brake cooling gear pump | |
Probable Cause
- Mechanical failure of parking brake release pump section (5). Refer to "Check: Check the parking brake release hydraulic filter.".
- Mechanical failure of hoist and front brake cooling gear pump (9). Refer to"Check: Check the front brake oil cooling filters. Check the screens for the rear brake oil coolers.".
- Mechanical failure of brake cooling pump section (8). Refer to "Check: Check the hoist and front brake cooling screens.".
Problem: Pieces of black fiber are found. These pieces are part of the brake disc.
Probable Cause
- Failure of the wheel brakes.
Problem: Shiny steel particles and/or chrome particles are found.
Probable Cause
- There is a mechanical failure of a hydraulic cylinder and/or of a cylinder rod. Inspect the cylinder rods for scoring.
Note: If any of the above particles are found during any visual checks, all components of the hydraulic system and of the brake cooling system must be cleaned. Do not use any damaged parts. Damaged parts must be replaced with new parts.