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Hot hydraulic oil under high pressure can remain in the components of the hydraulic system or the power train system after the engine has been stopped. The uncontrolled release of the hydraulic oil can cause sudden machine movement and can also result in the following conditions:
If hydraulic oil penetrates body tissue, the injury must be treated immediately by a doctor who is familiar with this type of injury. Use a board or a piece of cardboard to check for a hydraulic oil leak. Make sure that all of the attachments have been lowered to the ground and that all trapped pressure has been released from the hydraulic system and the power train system. Also, make sure that the hydraulic oil is cool before the removal of any components or lines. Remove the hydraulic oil filler cap only when the engine is stopped and the filler cap is cool enough to touch with your bare hand. |
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Personal injury can result if the machine moves while testing. If the machine begins to move during test, reduce the engine speed immediately and engage the parking brake. |
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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. |
The following test will determine if the pressure of the oil that is delivered to the service brakes from the brake valve is within the specified limit. Also, this test will determine whether the oil pressure to the brakes decreases to the specified limit when the brakes are activated.
Also, the test for brake lubrication is included in this story.
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| Illustration 1 | g01104724 |
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Tooling (A) | |
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| Illustration 2 | g01623868 |
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Tooling (B) | |
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| Illustration 3 | g01871217 |
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Tooling (F) | |
| Required Tools | ||||
|---|---|---|---|---|
| Tool | Item | Part Number | Description | Qty |
| A | A1 | 8T-0855 | Pressure Gauge ( |
1 |
| A2 | 8T-0863 | Pressure Gauge ( |
1 | |
| A3 | 6V-3989 | Fitting | 1 | |
| A4 | 6V-4143 | Quick Connect Coupler | 2 | |
| A5 | 177-7861 | Hose As ( |
1 | |
| B | 198-4240 | Digital Pressure Indicator Gp (DEALER TOOL) | 1 | |
| B1 | 198-4234 | Digital Indicator (PRESSURE) | 1 | |
| B2 | 198-4239 | Pressure Sensor Gp (DIGITAL) | 1 | |
| B3 | 198-4236 | Adapter Cable As (DIGITAL PRESSURE INDIAVSOR) | 1 | |
| F | F1 | 6V-3965 | Fitting | 1 |
| F2 | 3J-1907 | O-Ring Seal | 1 | |
| F3 | 5P-6944 | Adapter | 1 | |
| F4 | 3K-0360 | O-Ring Seal | 1 | |
Reference: Refer to Tool Operating Manual, NEHS0818, "Using the 198-4240 Digital Pressure Indicator Group" for more information on using Tooling (B).
Test Procedure (Remote Pressure Tap)
The following test procedure will determine if the pressure of the oil that is delivered from the brake valve is within the specified limit.
- Move the machine to a smooth horizontal location.
- Lower all of the implements. Engage the parking brake. Turn off the engine.
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Illustration 4 g01934233 - Locate pressure tap (R3). This pressure tap is located on the remote test panel on the left hand side of the machine.
- Assemble Tooling (A). Make sure that you use 8T-0855 Pressure Gauge (A1).
- Attach Tooling (A) or Tooling (B) to pressure tap (R3).
- Start the engine. Warm the power train oil to a temperature of
80° ± 10°C (176° ± 18°F) . - Operate the engine at high idle. Make sure that the transmission is in NEUTRAL and that the parking brake is in the OFF position.
- Check the pressure at Tooling (A1) or Tooling (B). The pressure at Tooling (A1) or Tooling (B) should be
2850 ± 150 kPa (413 ± 22 psi) . - Operate the engine at low idle (800 rpm). Make sure that the parking brake is in the OFF position.
- Check the pressure at Tooling (A1) or Tooling (B). The pressure at Tooling (A1) or Tooling (B) should be
2750 ± 150 kPa (399 ± 22 psi) . - The pressure at Tooling (A1) or Tooling (B) should be less than
70 kPa (10 psi) when the parking brake is fully engaged or when the service brake is fully engaged.Reference: See Testing and Adjusting, "Pressure Charts" in this module for additional pressure values.
The following test procedure will determine if the oil pressure that is delivered to the right brake is within the specified limit.
- Move the machine to a smooth horizontal location.
- Lower all of the implements. Engage the parking brake. Turn off the engine.
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Illustration 5 g01903575 Right brake
(1) Brake pressure port for the right brake
(2) Planetary gears and brake - Locate brake pressure port (1) inboard of right planetary gears and brake (2) toward the rear.
- Remove the plug from brake pressure port (1).
- Assemble Tooling (F). Install Tooling (F) in the location for brake pressure port (1).
- Assemble Tooling (A). Make sure that you use 8T-0855 Pressure Gauge (A1).
- Attach Tooling (A) or Tooling (B) to Tooling (F).
- Start the engine. Warm the power train oil to a temperature of
80° ± 10°C (176° ± 18°F) . - Operate the engine at high idle. Make sure that the transmission is in NEUTRAL and that the parking brake is in the OFF position.
- Check the pressure at Tooling (A1) or Tooling (B). The pressure at Tooling (A1) or Tooling (B) should be
2850 ± 150 kPa (413 ± 22 psi) . - Operate the engine at low idle (800 rpm). Make sure that the transmission is in NEUTRAL and that the parking brake is in the OFF position.
- Check the pressure at Tooling (A1) or Tooling (B). The pressure at Tooling (A1) or Tooling (B) should be
2750 ± 150 kPa (399 ± 22 psi) . - The pressure at Tooling (A1) or Tooling (B) should be less than
70 kPa (10 psi) when the parking brake is fully engaged or when the service brake is fully engaged.Reference: See Testing and Adjusting, "Pressure Charts" in this module for additional pressure values.
Note: For the left brake, remove the plug that is toward the front of the machine.
Perform Step 4 through Step 11 in "Test Procedure (Right Brake)" for the left brake on the other side of the machine.
Test Procedure (Right Brake Lubrication)
The following test procedure will determine if the pressure of the lubrication oil to the right brake is within the specified limit.
- Move the machine to a smooth horizontal location.
- Lower all of the implements. Engage the parking brake. Turn off the engine.
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Illustration 6 g01903576 Right brake
(2) Planetary gears and brake
(3) Test port for brake lubrication "LB2" - Locate the pressure port for brake lubrication (3) inboard of right planetary gears and brake (2) at the rear of the machine.
- Remove the plug from the pressure port for brake lubrication (3).
- Assemble Tooling (F). Install Tooling (F) in the pressure port for brake lubrication (3).
- Assemble Tooling (A). Make sure that you use 8T-0863 Pressure Gauge (A2).
- Attach Tooling (A) or Tooling (B) to Tooling (F).
- Start the engine. Warm the power train oil to a temperature of
80° ± 10°C (176° ± 18°F) . - Operate the engine at high idle. Make sure that the transmission is in NEUTRAL and that the parking brake is in the OFF position.
- Check the pressure at Tooling (A2) or Tooling (B). The pressure at Tooling (A2) or Tooling (B) should be
90 ± 35 kPa (13 ± 5 psi) . - Operate the engine at low idle (800 rpm). Make sure that the transmission is in NEUTRAL and that the parking brake is in the OFF position.
- Check the pressure at Tooling (A2) or Tooling (B). The pressure at Tooling (A2) or Tooling (B) should be
60 ± 25 kPa (9 ± 4 psi) .Reference: See Testing and Adjusting, "Pressure Charts" in this module for additional pressure values.
Test Procedure (Left Brake Lubrication)
Note: For the left brake, remove the plug that is toward the rear of the machine.
Perform Step 1 through Step 12 in "Test Procedure (Right Brake Lubrication)" for the left brake on the other side of the machine.
Note: The pressure at Tooling (A2) or Tooling (B) should be