Drift Check
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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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Personal injury or death can result from sudden movement of the lift cylinders or the tilt cylinders. Do not stand under the work tool when you are testing or adjusting the lift cylinders or the tilt cylinders. Do not stand under the lift arms when you are testing or adjusting the lift cylinders or the tilt cylinders. |
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This test will check the drift rate of the lift cylinders.
- Prepare the machine for troubleshooting.
Reference: Testing and Adjusting, "Machine Preparation for Troubleshooting".
- Start the engine. Warm the hydraulic oil to normal operating temperature. Normal operating temperature is 45 °C (115 °F) to 70 °C (160 °F). Use the following procedure in order to warm the hydraulic oil.
- Operate the engine at 1800 RPM to 2000 RPM.
- Extend the lift arms until the cylinders bottom out.
- Operate the tilt cylinders back and forth until you reach the normal operating temperature.
- Actuate the lift cylinders up and down for five repetitions. This will help to ensure that there is warm oil in the lift cylinders.
- Raise the work tool approximately 1 m (3.3 ft) off the ground. Move the lift control lever to the HOLD position.
Note: Do not move the hydraulic lockout control to the LOCKED position during the drift test.
- Turn the engine start switch to the OFF position.
- Observe the distance that the lift cylinder rod has moved. The maximum drift that is allowed is 2 mm (.08 inch) per minute.
- If the drift is greater than 2 mm (.08 inch) per minute, then isolate the lift cylinders and check the amount of drift. This will separate the possible causes of the drift.
- Start the engine. Lower the work tool to the ground. Turn the engine start switch to the OFF position.
Isolation Test
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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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Personal injury or death can result from sudden movement of the lift cylinders or the tilt cylinders. Do not stand under the work tool when you are testing or adjusting the lift cylinders or the tilt cylinders. Do not stand under the lift arms when you are testing or adjusting the lift cylinders or the tilt cylinders. |
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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, "Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on products. Dispose of all fluids according to local regulations and mandates. |
| Required Tools | ||
| Part Number | Description | Qty |
| 6V-9511 | Face Seal Plug | 1 |
| 6V-9746 | O-Ring Seal | 1 |
| 6V-9832 | ORFS Cap | 1 |
This test will help to determine whether one of the lift cylinders is causing a drift problem. When the oil port at the end of the lift cylinder is blocked, the lift cylinder should not move during a drift test. If the lift cylinder moves, there is internal leakage in one of the lift cylinders. If both cylinders are not drifting then there is probably a problem in the main control valve.
- Engage the parking brake.
- Install the steering frame lock.
- Start the engine. Raise the lift arms until the work tool is approximately 1 m (3.3 ft) off the ground. Position support blocks under the work tool. Lower the work tool onto the support blocks.
- Turn the engine start switch to the OFF position.
- When the engine is no longer running, turn the key start switch to the ON position. Move the hydraulic control levers to all positions in order to release the pressure in the hydraulic system.
- Push in the plunger for the breaker relief valve in order to relieve the pressure in the hydraulic tank.
- Release all hydraulic pressure before any fitting, any hose, or any component is loosened, tightened, removed, or adjusted.
Reference: Testing and Adjusting, "Hydraulic System Pressure - Release".
- Disconnect hose assembly (1) from the tube assembly. This will allow you to test the lift cylinder on the left side of the machine. Install a 6V-9511 Face Seal Plug with 6V-9746 O-Ring Seal in the hose that is connected to the head end of the lift cylinder. Install a 6V-9832 ORFS Cap onto the 164-6861 Union that is connected to the tube assembly.
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| Illustration 1 | g00865885 |
Hose Assemblies for the Lift Cylinders (Head End) | |
- Start the engine. Tilt the work tool to the full TILTBACK position. This will remove the work tool from the support blocks. Remove the support blocks.
- Turn the engine start switch to the OFF position. Leave the lift arms in this position. Place the lift lever in the full LOWER position. Record the amount of rod movement of that lift cylinder. The maximum drift that is allowed is 2 mm (.08 inch) per minute.
- After you establish the lift cylinder drift on the left side of the machine, start the engine. Position the support block under the work tool. Push the tilt control lever until the work tool is setting on the support blocks. Ensure that the weight of the work tool is supported by the support blocks.
- Turn the engine start switch to the OFF position. When the engine has stopped, place the key start switch in the ON position. Move the lift control lever and the tilt control lever in order to relieve the pressure in the hydraulic system. Place the key start switch in the OFF position.
- Push in the plunger for the breaker relief valve in order to relieve the pressure in the hydraulic tank. Ensure that all the hydraulic pressure is relieved from the system.
- Remove the 6V-9511 Face Seal Plug with 6V-9746 O-Ring Seal from the hose that connects to the head end of the lift cylinder. Remove the 6V-9832 ORFS Cap from the 164-6861 Union that is connected to the tube assembly. Install the hose assembly to the 164-6861 Union that is connected to the tube assembly.
- If lift cylinder has too much drift, the lift cylinder on the left side has an internal leak. Look for a scored cylinder and/or damaged piston seals. If the amount of cylinder drift is within the specification, the lift cylinder on the left is not causing the drift problem. The problem is probably in the lift cylinder on the right side or in the implement control valve.
- Start the engine and run the lift arms up and down for five repetitions. This will warm the hydraulic oil. This will purge any air that may have entered the hydraulic system.
- Repeat Steps 3 through 14 for the other lift cylinder. Hose assembly (2) will be used in order to test the drift on the lift cylinder on the right side of the machine.
- If the lift cylinder has too much drift, the lift cylinder on the right side has an internal leak. Look for a scored cylinder and/or damaged piston seals. If the amount of cylinder drift is within the specification, the lift cylinder on the right side is not causing the drift problem. There is probably a problem in the implement control valve.
- Start the engine and raise the lift arms in order to remove the work tool from the support blocks. Remove the support blocks. Lower the work tool to the ground.