| Required Tools | ||
| Part Number | Description | Qty |
| 8T-0860 | Pressure Gauge | 1 |
| 6V-4144 | Coupler | 1 |
| 1U-5482 | Pressure Adapter | 1 |
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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. |
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Sudden movement or accidental starting of the machine can cause personal injury or death to persons on or near the machine. To prevent personal injury or death, perform the following: Park the machine on a smooth, level surface. Lower the work tool to the ground and engage the parking brake. Stop the engine and remove the key. Block the wheels and install the steering frame lock. |
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| 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. |
- Park the machine on a smooth, level surface.
- Lower the blade to the ground.
- Engage the parking brake.
- Install the steering frame lock into the LOCKED position.
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| Illustration 1 | g00664484 |
- Start the engine. Lift the blade of the machine several times in order to warm the hydraulic oil.
- Turn the engine start switch to the OFF position. Lower the blade to the ground.
- Install a 8T-0860 Pressure Gauge with a 6V-4144 Coupler to pressure tap (2). The pressure tap is located on the discharge line of the implement pump (1) .
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| Illustration 2 | g00664722 |
- Remove bolts (4) that are holding cover (3) to the front frame. Remove cover (3) .
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| Illustration 3 | g00866440 |
Front Frame (3) Cover. (4) Bolts. | |
- Start the engine.
- Move the lift control lever to the full RAISE position. Raise the blade until the lift cylinder is fully retracted. Hold the lift control lever in the full RAISE position.
- Run the engine at high idle.
- Observe the pressure on the pressure gauge. The pressure should be 24100 ± 350 kPa (3500 ± 50 psi) at approximately 84 L/min (22 US gpm) for the 825H Soil Compactor. The pressure should be 24100 ± 350 kPa (3500 ± 50 psi) at approximately110 L/min (30 US gpm) for the 824H Wheel Tractor and the 826H Landfill Compactor.
- Lower the blade of the machine to the ground. Turn the engine start switch to the OFF position. If the pressure reading is correct, remove the pressure gauge. If the pressure reading is not correct, proceed to step 14 .
- Main relief valve (5) is located on the main control valve. In order to adjust the main relief valve, loosen locking nut (6). Turn adjuster (7) clockwise in order to increase the pressure. Turn adjuster (7) counterclockwise in order to decrease the system pressure.
Note: The 825H Soil Compactor will be equipped with a main control valve that has two sections. The 826H Landfill Compactor will be equipped with a main control valve that has one section. The main relief valve will be located in the same place.
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| Illustration 4 | g00866436 |
Typical Main Control Valve (5) Main relief valve. (6) Locking nut. (7) Adjuster. | |
- In order to verify that the pressure adjustment is correct, perform Step 9 through Step 12.
- When the pressure for the main relief valve is adjusted, start the engine and lower the blade to the ground. Turn the engine start switch to the OFF position and remove the test equipment.
- Install the cover that is over the main control valve.