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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine. |
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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, "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. |
Introduction
In order for the hydraulic system to function properly, each component in the system must be set to the correct specifications. Some components must be set prior to the testing of other components. A component that is not set properly will have an impact on other components in the system.
Specifications
| Lift Cylinder Cycle Time (sec) (± 0.5 sec) | ||||||
|---|---|---|---|---|---|---|
| Function | Raise | Lower | Float | |||
| Models | Std Flow | High Flow | Std Flow | High Flow | Std Flow | High Flow |
| 236D | 3.1 | 3.1 | 2.8 | 2.8 | 3.6 | 3.6 |
| 242D, 257D, 259D | 4.4 | 4.4 | 3.2 | 3.2 | 3.6 | 3.6 |
| 246D, 277D, 279D | 3.1 | 3.1 | 2.8 | 2.8 | 4.0 | 3.6 |
| 262D, 287D, 289D | 4.6 | 4.0 | 3.6 | 3.6 | 4.6 | 3.6 |
| 272D, 272D XPH | 5.2 | 4.4 | 3.7 | 3.6 | 4.6 | 4.7 |
| 297D, 297D XHP, 299D, 299D XPH | 5.2 | 4.4 | 3.7 | 3.6 | 4.6 | 4.7 |
| Tilt Cylinder Cycle Time (sec) (± 0.5 sec) | ||||
|---|---|---|---|---|
| Function | Dump | Tilt Back | ||
| Models | Std Flow | High Flow | Std Flow | High Flow |
| 236D | 2.4 | 2.4 | 2.0 | 2.0 |
| 242D, 257D, 259D | 2.4 | 2.4 | 2.0 | 2.0 |
| 246D, 277D, 279D | 2.5 | 2.1 | 1.8 | 1.8 |
| 262D, 287D, 289D | 2.3 | 2.1 | 1.8 | 1.8 |
| 272D, 272D XPH | 2.3 | 2.1 | 2.2 | 1.7 |
| 297D, 297D XHP, 299D, 299D XPH | 2.3 | 2.1 | 2.2 | 1.7 |
| Quick Coupler Cycle Time (Speed) (all standard flow models) | ||
| Description | Specification | Actual |
| Quick coupler ENGAGE | 10.0 seconds max | |
| Quick coupler DISENGAGE | 10.0 seconds max | |
| Maximum Cylinder Drift Rate | ||
| Description | Specification | Actual |
| Tilt Cylinder | 1 Minute 3 mm (0.12 inch) |
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| Lift Cylinder | 1 Minute 3 mm (0.12 inch) |
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Test Preparation
Before any tests are performed, visually inspect the complete hydraulic system for oil leaks and damaged parts. Refer to Testing and Adjusting, "Visual Inspection". Before any tests are performed, prepare the machine for troubleshooting. Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".
Test Procedure
The following operational checks can be used for the following items:
- Find leakage in the system.
- Determine whether the electrohydraulic controls are functioning correctly.
- Determine whether the pumps and motors are functioning correctly
- Determine whether the whole work tool system is functioning correctly.
Lift Cylinder Speed Check
Note: Perform the lift cylinder speed check without a work tool on the coupler.
- Fasten seat belt and lower armrest.
- Start the engine.
- Disengage the parking brake.
- Move the automatic leveling switch to the OFF.
- Run the engine at HIGH idle with the hydrostatic joystick in the NEUTRAL position.
- Operate the lift cylinder through at least five cycles. Operating the cylinders will ensure that there is warm oil in the lift cylinders.
- Tilt the work tool coupler to the full TILT BACK position. Lower the work tool coupler to the full lower position.
- Move the work tool joy stick to the FULL BACK position. Raise the work tool coupler from the full LOWER position to the full RAISE. Record the time from the full LOWER position to the full RAISE position.
- Move the work tool joy stick to the FULL FORWARD position. Lower the work tool coupler from the full RAISE position to the full LOWER position. Record the time from the full RAISE position to the full LOWER position.
If the speed is not with in specifications refer to Testing and Adjusting, "Hydraulic System Troubleshooting".
Tilt Cylinder
Note: Perform the tilt cylinder speed check without a work tool on the coupler.
- Fasten the seat belt and lower the armrest.
- Start the engine.
- Run the engine at HIGH idle with the hydrostatic joystick in the NEUTRAL position.
- Operate the tilt cylinders through at least five cycles. This function will ensure that there is warm oil in the tilt cylinders.
- Tilt the work tool coupler to the full TILT BACK position. Raise the work tool coupler to the full RAISE position.
- Move the work tool JOY STICK to the FULL RIGHT position. Tilt the work tool coupler from the full TILT BACK position to the full TILT FORWARD position. Record the time from the full TILT BACK position to the full TILT FORWARD position.
- Move the work tool JOY STICK to the FULL LEFT position. Tilt the work tool coupler from the full TILT FORWARD position to the full TILT BACK position. Record the time from the full TILT FORWARD position to the full TILT BACK position.
- Lower the work tool coupler to the ground.
Electric Quick Coupler Check (if equipped)
Note: Inspect the quick coupler and remove any debris that may affect the operation.
- Fasten the seat belt and lower the armrest.
- Start the engine.
- Disengage the parking brake.
- Run the engine at HIGH idle with the hydrostatic joystick in the HOLD position.
- Press the switch in order to engage the quick coupler. Record the time that is needed to engage the quick coupler. Press the switch in order to disengage the quick coupler. Record the time that is needed to disengage the quick coupler.
Drift Check (Lift and Tilt Cylinder)
Before performing a drift check, inspect the following areas for external leaks and sticking:
- Check for leakage at the cylinders wiper seal.
- Check for pin hole leaks in the cylinders welded joints.
- Inspect the work tool control valve for leaks.
- Inspect all hoses, tubes, and fittings for leaks.
Note: Perform the following test with a 1829 mm (72 inch) general-purpose bucket. If a general-purpose bucket is not available, use a load of 200 kg (441 lb).
- Warm the machine to 50° ± 10°C (122° ± 18°F).
Note: Measure the temperature inside the hydraulic tank.
- Operate the tilt cylinders for a minimum of five cycles in order to ensure that the oil in the cylinders is warm.
- Operate the lift cylinders for a minimum of five cycles in order to ensure that the oil in the cylinders is warm.
- Raise the lift arms approximately 1 m (3.3 ft) off the ground. Use the bucket pin as a reference point.
| Illustration 1 | g02155360 |
Typical example | |
- Tilt the bucket until the bucket is parallel to the ground.
- Turn the engine OFF. Mark the cylinders rod with an adhesive note or use adhesive tape. Measure distance from wiper seal to mark.
Note: For tilt cylinder drift, you will measure any "extension" of the rod. Place your marker on the rod so that the edge of the marker is flush with the end of the cylinder. For lift cylinder drift, you will measure any "retraction" of the rod. Start by placing your marker on the rod so that the edge of the marker is well above the end of the cylinder.
Note: Watch for unexpected movement of the cylinder which can cause pinching or a crushing injury.
| Illustration 2 | g01560392 |
Measuring tilt cylinder drift | |
| Illustration 3 | g01560905 |
Measuring lift cylinder drift | |
- Start a stopwatch.
- After 2 minutes, measure the displacement of the cylinder with a small ruler.
Note: Watch for unexpected movement of the cylinder which can cause pinching or a crushing injury.
Note: If the cylinder drift exceeds the maximum, refer to Testing and Adjusting, "Hydraulic System Troubleshooting" for probable causes.
- Start the engine and lower the bucket to the ground.
Check for the Operation of the Two Speed Function (if equipped)
Note: The multifunction switch must be in the Two Speed position in order to activate the two speed function on the left-hand joystick . Refer to the Operation and Maintenance Manual, "Operator Controls", for a complete description of the two speed operation.
- Fasten seat belt and lower armrest.
- Start the engine run the engine at HIGH idle
- Disengage the parking brake.
- Move hydrostatic joystick lever to the full FORWARD position.
- While you keep the machine at full speed, press the switch in order to activate the rabbit mode. There should be a noticeable increase in the speed of the machine and the indicator for two speed should light. If there is not a noticeable increase in the speed of the machine, refer to the Testing and Adjusting, "Hydrostatic System Troubleshooting".
- While the machine is still traveling, press the switch in order to deactivate the rabbit mode. There should be a noticeable decrease in the speed of the machine and the indicator for two speed should shut off. If there is not a noticeable decrease in the speed of the machine, refer to the Testing and Adjusting, "Hydrostatic System Troubleshooting".
