5130B Excavator Hydraulic System Caterpillar

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Hydraulic oil pressure can remain in the hydraulic oil system on this machine after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, refer to the procedure in Testing and Adjusting Manual, "Release of Pressure in the Hydraulic System". When possible, the bucket must always be lowered to the ground before service is started. When it is necessary for the boom to be in the raised position while tests or adjustments are done, be sure that the boom, stick and bucket have correct support. Be sure the swing parking brakes and the travel parking brakes are on and the brake release lines are disconnected and plugged. Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.

Release of Pressure in the Hydraulic System

Release the pressure in the implement hydraulic circuits (boom, stick and bucket) before any hydraulic lines or components are disconnected or removed.

1. Fully retract the rod in the stick cylinder.

2. Adjust the position of the bucket as the boom is lowered. The bucket must rest flat on the ground.

3. Lower the boom until the bucket is flat on the ground.

4. Shut off the engine.

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Illustration 1	g00448055
Pilot Manifold (1) Test port

5. Check the pilot pressure at the test port (1) for the implement pilot system on the pilot manifold under the cab. If the pressure is below 3000 kPa (435 psi) connect an auxiliary pump unit to this port and pump the pilot pressure to 4500 kPa (630 psi).

6. Put the hydraulic activation control lever in the UNLOCK position. Turn the engine start key to the ON position. Do not start the engine.

7. Move the control levers for the boom, the stick, the bucket and swing to each of the FULL STROKE positions. Actuate both the trigger switches for the front shovel bucket bottom dump controls. This should release any pressure that might be present in the main implement system. Disconnect the auxiliary pump unit (if used) and install the pressure gauge at the test port. Continue to move the control levers until the pilot system pressure is released. Use a pressure gauge to verify that the pilot system pressure is released.

8. Press the button on the vacuum breather relief valve in order to release the hydraulic tank pressure. The vacuum breather relief valve is located on the hydraulic tank.

9. The pressure in the system has been released and lines and components can be removed or disconnected.

Introduction

Note: Run the Machine Control Module tests and check the event list on the Vital Information Management System (VIMS) before troubleshooting the hydraulic system.

1. Correct oil flow and pressure are necessary for correct operation. Pump output, or the oil flow is dependent on the engine speed. Oil pressure is caused by resistance to the oil flow.

2. Always warm the hydraulic oil to a minimum temperature of 50°C (122°F) before starting any testing and adjusting procedure.

3. Use the following engine speeds during testing.

   Low Idle ... 725 ± 20 rpm

   Full Load ... 1750 ± 20 rpm

   High Idle ... 1810 ± 20 rpm

4. The control valve spools for the boom, the stick and the bucket are connected in parallel. The front control valve is composed of these control valve spools. The front control valve is supplied with hydraulic oil from the four implement piston pumps.

5. The control valve spools for the right track, the left track and the bottom dump are connected in parallel. The rear control valve is composed of these control valve spools. The rear control valve is supplied with hydraulic oil from the four implement piston pumps.

6. Each of the implement circuits has a check valve which prevents cylinder drift during spool movement. Each implement circuit has makeup valves. The makeup valves allow the flow of oil to both ends of the cylinders and the motors. There is also a line relief valve for each of the circuits.

7. Main hydraulic system pressure is controlled by the load sensing signal relief valve. The load sensing signal relief valve has two settings. The load sensing signal relief valve is set at 31000 ± 500 kPa (4500 ± 75 psi) for the implement circuit. The load sensing signal relief valve is set at 35000 ± 500 kPa (5080 ± 75 psi) for the travel circuit.

8. During all machine operations, a relief valve for the load sensing signal that is set too low will result in lower implement forces and in the possibility of increased cycle times.

9. The margin relief valve is located on the rear of the front control valve. The margin relief valve is set to open when the discharge pressure of the implement piston pump is 3000 kPa (435 psi) above the load sensing pressure.

10. During individual circuit operation, a line relief valve that is set too low may result in the following problems: increased cycle times, excessive heat in the hydraulic system, poor performance and noise from the opening and closing of the line relief valve. The line relief valves for the bottom dump circuit, the boom circuit, the stick circuit and the bucket circuits are set to open at 33500 ± 350 kPa (4860 ± 50 psi). The line relief valves for the travel circuit are set to open at 38000 ± 700 kPa (5515 ± 100 psi).

11. The front control valve spools are actuated by pilot system pressure from the implement pilot valves. The spools in the rear control valve are actuated by different sources. The travel spools are actuated by pilot system pressure from the travel pilot valves. The bucket bottom dump solenoids will actuate the bottom dump spool. The pressure in the pilot system is regulated by the low pressure pilot relief valve.

12. Swing system pressure is set by the swing dual pressure relief valve. The swing dual pressure relief valve is set to open at 35000 ± 1000 kPa (5080 ± 145 psi) during swing acceleration. Machines with serial numbers 4CS001-183 the swing dual pressure relief valve is set to open at 25000 ± 1000 kPa (3630 ± 145 psi) during swing deceleration. Machines with swing drive systems that have been updated and machines with serial numbers, 4CS184-UP the swing dual pressure relief valve is set to open at 28500 ± 1000 kPa (4130 ± 145 psi) during swing deceleration.

13. The swing pump has a high pressure cutoff compensator which is set at a pressure above the swing relief pressure. The compensator is factory set at 39000 kPa (5660 psi).

    Note: Do not adjust the high pressure cutoff compensator.

14. The travel parking brakes are applied by spring force. It is necessary for hydraulic pressure from the low pressure pilot system to release the travel parking brakes before the machine can be moved.

15. The swing parking brakes are applied by spring force. It is necessary for hydraulic pressure from the low pressure pilot system to release the swing parking brakes before the machine can be swung.

16. The low pilot system pressure is set at 4000 kPa (580) at throttle position 10. For machines with a swing drive system that have been updated, the low pilot system pressure is set at 4500 ± 200 kPa (630 ± 30 psi). At throttle position 1, the low pilot system pressure should be at least 3100 kPa (450 psi). The swing parking brakes and the travel parking brakes require the pilot pressure to be at least 3000 kPa (435 psi) in order to fully release.

17. A hydraulic pressure setting that is too high can cause a decrease in the service life of the hoses and the couplings.

18. When you are troubleshooting a possible problem perform visual checks and measurements first. Next, perform the operational checks. Last, perform the testing and adjusting procedures.

Warm Up Procedure For The Hydraulic Oil

It is important to warm the hydraulic oil before you perform most tests.

1. Start the engine.

2. Set the throttle switch to position "10".

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Illustration 2	g00611396
(1) "GAUGE" key (2) Message area for VIMS

3. Use the Vital Information Management System (VIMS) to obtain the hydraulic oil temperature. Use the keypad to type "500" in the message area (2). Press "GAUGE" key (1). This will cause message area (2) to display the hydraulic oil temperature.

4. Stall the bucket curl function. Hold the bucket in the stall condition.

5. Cycle the boom function until the hydraulic oil temperature reaches 50 °C (122 °F).

Disconnect The Travel Parking Brakes

Some tests require the travel controls to be moved. This procedure will ensure that the travel brakes will not release when the travel function is actuated.

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Illustration 3	g00638108
Swivel (1) Port to the travel parking brakes

1. Disconnect brake release line (1) .

2. Install a 6V-9508 Face Seal Plug in the brake release line.

3. Cover the port with a cloth in order to prevent contamination from entering the hydraulic system.

Disconnect The Swing Parking Brakes

Some tests require the swing controls to be moved. This procedure will ensure that the swing brakes will not release when the swing function is actuated.

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Illustration 4	g00407292
Left swing drive (1) Brake release line

1. Disconnect brake release line (1) for the swing parking brakes at the left swing drive.

2. Install a 6V-9508 Face Seal Plug in the brake release line.

3. Cover the port with a cloth in order to prevent contamination from entering the hydraulic system.