The Operational Checks can be used in order to find any of the following problems: leakage in the system, a bad valve and a bad pump. The speed of the rod movement can be measured in order to check the condition of the cylinders and the condition of the pump.
The oil in the hydraulic system must be the oil which is recommended in the Operation and Maintenance Manual, and at a temperature of
Extend the cylinder and retract the cylinder. Repeat several times for each cylinder.
- Watch the operation of the cylinder. Movement must be uniform and regular.
- Listen for noise from the pump.
- Listen for the sound of the line relief valves. The relief valves must not open while the attachment cylinders are in motion.
The drift rates change with different conditions of the hydraulic components. The drift rates change with machine operation, hydraulic oil temperature, etc. Before you measure drift of the cylinder rods, the cylinders must be extended at least five times.
Cylinder rod drift is caused by the following conditions:
- Loose oil line connections or damaged oil lines with oil leaks
- Leakage around the piston seals in the cylinder
- Leakage in the control valve (worn valve section and worn spool valve)
- Leakage through check valves or makeup valves
- Leakage through the dead engine lower valves
Measure lift cylinder rod drift by using the following procedure:
- Check hydraulic oil temperature.
- Lift the bulldozer until the cutting edge is approximately
254 mm (10.0 inch) off the ground. With the lift control lever in the HOLD position, stop the engine. - Obtain a measurement of the distance of cylinder drift over time. Compare this distance to the values in the chart.
Note: The drift distances in the chart are for new machines.
| Lift Cylinder Drift | |||
|---|---|---|---|
| Oil Temperature | 38 to 49°C (100 to 120°F) | 49 to 66°C (120 to 150°F) | Over 66°C (Over 150°F) |
| Maximum Allowable Drift | |
|
|
| Time Interval (minutes) | 5.0 | 2.7 | 1.7 |
Measure tilt cylinder rod drift by using the following procedure:
- Check hydraulic oil temperature.
- Fully retract the tilt cylinder.
- Lower the bulldozer in order to lift the front idlers off the ground. Move the control levers to the HOLD position and stop the engine.
- Obtain a measurement of the distance of cylinder drift over time. Compare this distance to the values in the chart.
Note: The drift distances in the chart are for new machines.
| Tilt Cylinder Drift | |||
|---|---|---|---|
| Oil Temperature | 38 to 49°C (100 to 120°F) | 49 to 66°C (120 to 150°F) | Over 66°C (Over 150°F) |
| Maximum Allowable Drift | |
|
|
| Time Interval (minutes) | 5.0 | 2.7 | 1.7 |
Drift Test for Ripper Cylinder
Measure ripper cylinder rod drift by using the following procedure:
- Check hydraulic oil temperature.
- Lift the ripper so that the ripper teeth are approximately
254 mm (10.0 inch) off the ground. Move the ripper control lever to the HOLD position. Stop the engine. - Obtain a measurement of the distance of cylinder drift over time. Compare this distance to the values in the chart.
Note: The drift distances in the chart are for new machines.
| Ripper Cylinder Drift | |||
|---|---|---|---|
| Oil Temperature | 38 to 49°C (100 to 120°F) | 49 to 66°C (120 to 150°F) | Over 66°C (Over 150°F) |
| Maximum Allowable Drift | |
|
|
| Time Interval (minutes) | 5.0 | 2.7 | 1.7 |
The oil in the system must be the oil which is recommended in Operation and Maintenance Manual, and at a temperature of
Identify the speed of each cylinder. Compare these values to the values in the chart. Equal values indicate normal circuit operation.
If the speed of a cylinder is too slow, check that circuit for cylinder drift.
| Speed Test of the Bulldozer Lift Cylinders | Speed (seconds) |
|---|---|
| RAISE (ground level to full RAISE) | 2.7 ± 0.2 |
| LOWER powerdown (full RAISE to ground level) | 1.6 ± 0.2 |
| LOWER (pause time at ground level) | 1.2 + 0.3 − 0.1 |
| LOWER (full RAISE to full LOWER) | 4.0 ± 0.2 |
| RAISE (full LOWER to full RAISE) | 3.6 ± 0.2 |
| LOWER float down (full RAISE to ground level) | 1.5 ± 0.2 |
| Speed Test of the Bulldozer Tilt Cylinder(s) | Speed (seconds) |
|---|---|
| TILT (full right to full left) | 1.3 ± 0.2 |
| TILT (full left to full right) | 1.3 ± 0.2 |
| Speed Test of the Bulldozer Angle Cylinders | Speed (seconds) |
|---|---|
| ANGLE (full left to full right) | 3.4 ± 0.2 |
| ANGLE (full right to full left) | 3.4 ± 0.2 |
| Speed Test of the Ripper Cylinders | Speed (seconds) |
|---|---|
| LOWER (full RAISE to full LOWER) | 2.4 ± 0.2 |
| RAISE (full LOWER to full RAISE) | 2.8 ± 0.2 |