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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak. |
| 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. |
| 950M/962M Backup Relief Valve Pressure | ||
|---|---|---|
| Date | Equipment ID Code | |
| Pump Pressure | Setting | Actual |
| Steering Backup Relief Valve | |
|
| |
| Illustration 1 | g03137041 |
|
The backup relief valve is located on the lower left side of the steering control valve behind the hydraulic service center. | |
| 950M/962M Torque Specifications | |
|---|---|
| Callout | Torque |
| Locknut (4) Steering Backup Relief Valve | |
The backup relief valve for the steering system is located on the steering control valve. The backup relief valve controls the pressure in the steering system in case the pressure control section of the steering pump fails.
The backup relief valve for the steering system is set to a higher pressure than the maximum system pressure (pump stall pressure). Therefore, the backup relief valve only operates if the control section of the steering pump fails to regulate the pump pressure to
This information includes the following test:
- Relief Valve (Pump Backup)
This information includes the following adjustment procedure:
- Adjustment Procedure Relief Valve (Pump Backup)
| |
| Illustration 2 | g02571852 |
|
Tooling (A) 198-4240 Digital Pressure Indicator Gp | |
| Tool | Item | Qty | Part No | Description |
|---|---|---|---|---|
| A | 198-4240 | Digital Pressure Indicator Gp | ||
| A1 | 1 | 198-4234 | Digital Indicator | |
| A2 | 1 | 198-4237 | Pressure Sensor Gp
(0 to 3,445 kPa (0 to 500 psi)) |
|
| A2 | 1 | 198-4238(1) | Pressure Sensor Gp
(0 to 34,450 kPa (0 to 5,000 psi)) |
|
| A2 | 1 | 198-4239 | Pressure Sensor Gp
(0 to 41,368 kPa (0 to 6,000 psi)) |
|
| A2 | 1 | 251-9600(2) | Pressure Sensor Gp
(0 to 68,900 kPa (0 to 10,000 psi)) |
|
| A3 | 1 | 198-4236 | Adapter Cable As | |
| (1) | This sensor must be purchased separately. The sensor is not included in the 198-4240 Digital Pressure Indicator Gp |
| (2) | This sensor can only be used on large diameter pressure taps like 6V-3965 Fitting. |
Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".
Refer to Testing and Adjusting, "System Pressure Release".
- Move steering frame lock to the LOCKED position.
- Engage the parking brake. Move the transmission direction selector to the NEUTRAL position.
| |
| Illustration 3 | g03137097 |
- Attach a
0 to 40000 kPa (0 to 5802 psi) pressure gauge to pressure tap (2). Pressure tap (2) is located on the right side of the machine in the hydraulic service center. - Start the engine. Operate the engine at high idle. Continuously stall the RACK BACK function while simultaneously raising the lift arms at full speed. When the lift arms are almost raised, cycle the tilt cylinder almost to the FULL DUMP position. Then move the tilt cylinders to the full RACK BACK position. Continuously stall the RACK BACK function and simultaneously lower the lift arms back to the ground level position. Without stalling the RACK BACK function, cycle the lift function to raise the lift arms fully. Then lower the lift arms in order to allow the pump to operate at low-pressure briefly and circulate oil through the system. Repeat this process in order to increase the temperature of the oil to normal operating temperature.
- After the oil has reached normal operating temperature, lower the bucket to the ground. Stop the engine.
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Illustration 6 g03137074 Backup relief valve (3) is located on the lower left side of the steering control valve behind the hydraulic service center.
(3) Backup relief valve for the steering system. (4) Locknut. (5) Adjustment screw for the backup relief valve. - Loosen locknut (4) on steering backup relief valve (3). Turn adjustment screw (5) counterclockwise by two full turns.
- Operator must be present in seat.
- The left armrest must be down.
- Start the engine. Position the bucket until the bucket is slightly off the ground. Run the engine at high idle.
Note: During the following step, do not keep the steering pump at stall condition for more than 10 seconds. If necessary, release the STIC control lever and wait for 30 seconds before you repeat the step.
- Move the STIC control level to articulate the machine against the steering frame lock. Continue to hold the STICK control lever in full articulation against the steering frame lock in order to obtain a reliable pressure reading.
- Record the pressure reading on the pressure gauge. The reading should be lower than
30600 ± 400 kPa (4438 ± 58 psi) . Turn adjustment screw (5) slowly in the clockwise direction while you observe the pressure gauge. The pressure reading should increase to306000 ± 400 kPa (44382 ± 58 psi) . Then, the pressure should stop rising.Note: The pressure stops rising because the steering pump has reached a stall condition. This process reduces pump output.
Note: The Piston Pump (Steering) High Pressure Stall - Test and Adjust procedure in this manual, must be performed before completing this test. The High Pressure cutoff must be set above
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| Illustration 4 | g02698538 |
| (1) Location of the remote pressure taps | |
| |
| Illustration 5 | g03137070 |
| (2) Pressure tap for the steering pump pressure | |
Adjustment Procedure (Relief Valve Pump Backup)
- When the pump stall pressure is reached, continue to turn adjustment screw (5) clockwise by one full turn. Tighten locknut (4) to a torque of
20 ± 3 N·m (14 ± 2 lb ft) . - Lower the bucket and any attachment to the ground. Stop the engine.
- See the reference at the start of this procedure for the correct method to release any hydraulic pressure that may be in the steering system. Remove the pressure gauge and the hydraulic line from pressure tap (2).
- Perform the Piston Pump (Steering) High Pressure Stall - Test and Adjust procedure in this manual, to return the high-pressure cutoff to the correct setting.