 |
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 |
|---|
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. |
| NOTICE |
|---|
Do not adjust the main relief valve above the specified pressure. Adjustment of the main relief valve above the specified pressure may cause damage to the gear pump. |
Specifications
| Main Relief Valve Specifications | ||
| Description | Specification | Actual |
| All Standard Flow Models | 23000 ± 700 kPa (3335 ± 102 psi) |
|
| 236D, 242D, 257D, 259D High Flow | 23000 ± 700 kPa (3335 ± 102 psi) |
|
| All High Flow (XPS) and (XHP) Models | 23000 ± 1000 kPa (3335 ± 145 psi) |
|
Introduction
The following test is performed in order to determine if the main relief valve for the work tool is damaged or improperly set.
Required Tools
| Illustration 1 | g02571852 |
Tooling (A) 198-4240 Digital Pressure Indicator Gp | |
| Illustration 2 | g02726620 |
| Tool | Item | Qty | Part No | Description |
|---|---|---|---|---|
| A | 198-4240 | Digital Pressure Indicator Gp | ||
| A | A1 | 1 | 198-4234 | Digital Indicator |
| A2 | 1 | 198-4239 | Pressure Sensor Gp (0 to 41,368 kPa (0 to 6,000 psi)) |
|
| A3 | 1 | 198-4236 | Adapter Cable As | |
| B | B1 | 1 | 8T-08656 | Pressure Gauge (0 TO 6,000-KPA (0 TO 970-PSI)) |
| B2 | 1 | 6V-3989 | Fitting | |
| B3 | 2 | 6V-4143 | Quick Connect Coupler | |
| B4 | 1 | 177-7861 | Hose As 4.3 m (14 ft) |
|
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
- Engage the parking brake. Stop the engine.
- Raise the cab. refer to Operation and Maintenance Manual, "Cab Tilting" for tilting procedure.
- Install either Tooling A or Tooling B to Pressure tap (2) .
| Illustration 3 | g03410708 |
Typical example of Standard Flow Valve (1) Load sensing relief valve (2) Pressure tap | |
| Illustration 4 | g03410759 |
| Illustration 5 | g03410716 |
Typical example of High Flow Valve (1) Load sensing relief valve (2) Pressure tap | |
- Lower cab. Secure the hydraulic line so that the pressure gauge can be viewed by the operator during test. Make sure that the hoses are not pinched when the cab is lowered.
- Sit in the operator seat. Fasten the seat belt. Lower the armrest. Disengage the parking brake.
Note: The oil in the hydraulic system must be at an operating temperature of 50° ± 10°C (122° ± 18°F). This temperature range is specified for standard factory fill oil only. Use the Electronic Technician Software in order to monitor this temperature. Or refer to Testing and Adjusting, "Hydraulic Oil Temperature Test" for an alternate procedure.
- Run the engine at HIGH IDLE.
- With no work tool high flow work tool connected the machine roll the right-hand thumb wheel above 80%, record pressure.
Note: Do not stall the hydraulic system for more than 10 seconds. If necessary, release the work tool from the stall condition. After 30 seconds have passed, repeat Step 7.
- If the pressure reading is within specifications, proceed to step10. Refer to table 1
- If pressure reading is not within specifications, refer to the section titled "Hydraulic Troubleshooting" in this manual.
- Release the hydraulic system pressure. Refer to Testing and Adjusting, "Hydraulic System Pressure Release" for the proper procedure.
- Raise the cab and remove Tooling (A). Refer to Operation and Maintenance Manual, "Cab Tilting".
