572R Pipelayer Hydraulic System Caterpillar

Testing and Adjusting

Usage:

572R 2HZ

Implement Hydraulic System

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Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine.

To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.

Move the machine to a smooth horizontal location. Move away from working machines and personnel. Lower the boom to the ground.

Allow only one operator on the machine. Keep all other personnel away from the machine or in the view of the operator.

Engage the parking brake.

Stop the engine.

Move the control levers for the hydraulic system to all of the positions in order to release the pressure in the hydraulic system.

Carefully loosen the filler cap on the hydraulic tank in order to release the pressure in the tank.

Make sure that all of the hydraulic pressure is released before any fittings, hoses or components are loosened.

Tighten the filler cap on the hydraulic tank.

Make sure that the oil temperature is within the acceptable limits before removing lines or components.

Perform the procedure to discharge the hydraulic accumulator.

The pressure in the system has now been released and the lines and components can be removed.

Procedure to Discharge the Hydraulic Accumulator

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Pressurized fluids can cause injury or death.

Before disassembling any lines, controls, or accumulator, be sure that the pilot system hydraulic accumulator pressure is zero.

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Illustration 1	g00488027
Location of the pressure tap for the accumulator

Attach a 0 to 7000 kPa (0 to 1000 psi) pressure gauge to the pressure port that is shown. This pressure tap is on the boom and hook control valve which is located below the floorplate in the operator's compartment.

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Illustration 2	g00488039
Hook control lever (1) QUICK-DROP (2) LOWER (3) HOLD (4) RAISE

Move the hook control lever to the RAISE position. Then, move the control lever to the HOLD position. Repeat this procedure several times.

The needle on the pressure gauge should quickly drop to 0 kPa (0 psi) .

If the gauge does not show any pressure, the accumulator has been discharged.

During a diagnosis of the hydraulic system, remember that the correct oil flow and pressure are necessary for correct operation. The output of the pump may increase with an increase in engine speed. Oil pressure is caused by a resistance to the output or oil flow.

Visual Checks

A visual inspection of the hydraulic system and the corresponding components is the first step in order to identify a problem.

Make the following inspections.

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Personal injury or death can result from improperly checking for a leak.
Always use a board or cardboard when checking for a leak. Escaping air or fluid under pressure, even a pin-hole size leak, can penetrate body tissue causing 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.

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Boom must be raised and lowered through its full arc to test the hydraulics.

To avoid personal injury, perform this test in an area with sufficient boom clearance especially from electrical power line contact and that is free of personnel. Prevent machine movement by applying the parking brake.

Check all of the implement oil line connections for damage or leaks.

Trace all of the oil lines from the implement connections to the valve connections. Check the lines and the connections for damage or leaks.

Check the pump and the connections for damage or leaks.

Trace the pump lines to the tank and the valves. Check the lines and the tank for damage or leaks.

Check the oil level in the tank.

Use a clear bottle or a container in order to get an oil sample immediately after the machine is stopped. Check for air bubbles in the oil sample.

Remove the filter element and check for particles that are removed from the oil by the filter. A magnet can be used in order to separate ferrous material from the nonferrous particles in the filter.

Pump Efficiency Check

This test is designed to determine if a pump is operating within the design parameters. A bench test is the only test which is presently available. Perform this test only when all of the cylinder cycle times are too slow and the resolver network check is okay.

For any pump test, the pump flow at 690 kPa (100 psi) will be larger than the pump flow at 6900 kPa (1000 psi) if the pump is operating at the same rpm. The pump flow is measured in L/min (US gpm).

The difference between the pump flow of two operating pressures is the flow loss.

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Table 1
Method for determining flow loss
	Pump flow at 690 kPa (100 psi)
−	Pump flow at 6900 kPa (1000 psi)
	Flow loss

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Table 2
Example of determining flow loss
	2176 L/min (57.5 US gpm)
−	196.8 L/min (52.0 US gpm)
	20.8 L/min (5.5 US gpm)

Flow loss is used as a measure of pump performance. Flow loss is expressed as a percentage of pump flow.

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Table 3
Method of determining percent of flow loss
Flow loss (L/min or US gpm)	×	100	=	Percent of flow loss
Pump flow at 690 kPa (100 psi)

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Table 4
Example of determining percent of flow loss
20.8 L (5.5 US gal)	×	100	=	9.5%
217.6 L/min (57.5 US gpm)

If the percent of flow loss is greater than 10%, the pump performance is inadequate.

Note: The values in the examples are not set values for any specific pump or for any specific pump condition. Refer to the Hydraulic Specifications, RENR2028 for the pump flow of a new pump at 690 kPa (100 psi) and at 6900 kPa (1000 psi) .

Test on the Machine

Install a flow meter. Run the engine at high idle. Measure the pump flow at 690 kPa (100 psi), and at 6900 kPa (1000 psi). Use these values in the following formula.

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Table 5
Method of determining percent of flow loss
Flow loss (L/min or US gpm)	×	100	=	Percent of flow loss
Pump flow at 690 kPa (100 psi)

Test on the Bench

If the test bench can be run at 6900 kPa (1000 psi) and at full pump rpm, determine the percent of flow loss by using the above formula.

If the test bench can not be run at 6900 kPa (1000 psi) or at full pump rpm, run the pump shaft at 1000 rpm. Measure the pump flow at 690 kPa (100 psi) and at 6900 kPa (1000 psi). Use these values in the top portion of the following formula. For the bottom part of the formula, run the pump shaft at 2000 rpm. Measure the pump flow at 690 kPa (100 psi).

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Table 6
	Pump flow at 690 kPa (100 psi)
−	Pump flow at 6900 kPa (1000 psi)	×	100	=	Percent of flow loss
	Pump flow at 690 kPa (100 psi) and at 2000 rpm

Testing and Charging the Accumulator

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Table 7
Tools Needed
Tool	Part Number	Part Description	Qty
A	7S-5437	Nitrogen Charging Apparatus	1

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Dry nitrogen is the only gas approved for use in the accumulator. Charging the accumulator with oxygen gas will cause an explosion. This danger will not happen if nitrogen cylinders with standard CGA (Compressed Gas Association, Inc. ) Number 580 connections are used. When you order nitrogen gas, be sure that the cylinders are equipped with CGA No. 580 Connections. Do not use color codes or other methods of identification to tell the difference between nitrogen and oxygen cylinders.

Gas pressure is variable with the temperature. The accumulator must be at the same temperature as the surrounding air before the accumulator can be checked or charged. Use the following chart to get the correct nitrogen charge.

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Table 8
Charging Pressure and Temperature Relationship for the Accumulator
Temperature	Pressure ⁽¹⁾
−7°C (20°F)	3100 kPa (450 psi)
−1°C (30°F)	3170 kPa (460 psi)
4°C (40°F)	3240 kPa (470 psi)
10°C (50°F)	3310 kPa (480 psi)
16°C (60°F)	3375 kPa (490 psi)
21°C (70°F)	3445 kPa (500 psi)
27°C (80°F)	3515 kPa (510 psi)
32°C (90°F)	3580 kPa (520 psi)
38°C (100°F)	3650 kPa (530 psi)
43°C (110°F)	3720 kPa (540 psi)
49°C (120°F)	3790 kPa (550 psi)

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^( 1 )

The allowable tolerance on nominal pressure is 70 kPa (10 psi) .

Note: For an accumulator precharge of 345 kPa (500 psi), the pressure change is 70 kPa (10 psi) per 5.5°C (10°F) difference from the operating temperature.

Do not use an adapter to connect the nitrogen charging equipment to a valve that can be used on oxygen cylinders or gas cylinders. Use dry nitrogen.

The pressure of the hydraulic oil on the accumulator must be removed before the accumulator is tested or charged. Shut off the engine and perform the procedure to discharge the accumulator.

Testing the Nitrogen Charge

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Illustration 3	g00281220
Nitrogen charging apparatus (1) Pressure gauge. (2) Connection to nitrogen cylinder valve. (3) Regulator assembly. (4) Valve. (5) Pressure gauge. (6) Pressure regulating screw. (7) Valve handle. (8) Chuck.

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Illustration 4	g00488300
Accumulator (9) Cap (10) Accumulator

Remove cap (9) from the top of accumulator (10) .

Close valve (4) . Use 6890 kPa (1000 psi) gauge (5) to check the nitrogen charge in the accumulator.

Install chuck (8) on the valve of the accumulator.

Turn valve (7) on chuck (8) clockwise. Check the temperature of the air around the accumulator. The pressure on the gauge must be within the tolerances that are listed in Table 8 .

If the pressure reading on the gauge is too high, lower the pressure by slowly opening valve (4) .

If the pressure reading on the gauge is too low, charge the accumulator.

Charging the Accumulator

Connect the hose from the nitrogen cylinder to valve (4) .

Close valve (4) .

Open the valve on the nitrogen cylinder. Adjust screw (6) on the regulator assembly until gauge (1) is at the pressure that will charge the accumulator. Use Table 8 as a reference for the correct charging pressure.

When the pressures on gauge (5) and on gauge (1) are identical, turn off valve (4) .

If there is a decrease in pressure on gauge (5) , open valve (4) . This allows more nitrogen to enter the accumulator.

Repeat Steps 4 and 5 until the following items occur:
- Pressure readings of gauges (5) and (1) are identical.
- Pressure readings do not change.

Close the valve on the nitrogen cylinder.

Turn valve (7) on chuck (8) counterclockwise.

Remove the test equipment and install cap (9) on accumulator (10) .

Testing and Adjusting the Main Hydraulic Pump

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Illustration 5	g00471417
Hydraulic pump assembly (1) Main hydraulic pump (2) Auxiliary hydraulic pump

There are two hydraulic pumps for the hydraulic system. Main hydraulic pump (1) is a piston type pump which supplies the drawworks with pressure. Auxiliary hydraulic pump (2) is a gear pump which supplies oil to the counterweight circuit and the lubrication circuit. Auxiliary hydraulic pump (2) is not adjustable.

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Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine.

To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.

Move the machine to a smooth horizontal location. Move away from working machines and personnel. Lower the boom to the ground.

Allow only one operator on the machine. Keep all other personnel away from the machine or in the view of the operator.

Engage the parking brake.

Stop the engine.

Move the control levers for the hydraulic system to all of the positions in order to release the pressure in the hydraulic system.

Carefully loosen the filler cap on the hydraulic tank in order to release the pressure in the tank.

Make sure that all of the hydraulic pressure is released before any fittings, hoses or components are loosened.

Tighten the filler cap on the hydraulic tank.

Make sure that the oil temperature is within the acceptable limits before removing lines or components.

Perform the procedure to discharge the hydraulic accumulator.

The pressure in the system has now been released and the lines and components can be removed.

Margin Pressure

The margin pressure is the additional pump pressure that is above the required pressure. The pump output is always above the pressure that is required by the system. Perform the following test in order to ensure that the margin pressure is set accurately.

Remove the guards that cover the winch components and lines on the right side of the operator's compartment. Remove the floorplate and disconnect the control levers. Remove the lever assembly.

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Illustration 6	g00488438
Load sensing manifold (LS) Load sensing port

Install a pressure tap in the line that is connected to port (LS) on the load sensing manifold. The load sensing manifold is located below the guard on the right side of the operator's compartment. Connect a 35000 kPa (5000 psi) pressure gauge to the pressure tap.

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Illustration 7	g00488504
Boom and hook control valve (TP1) Pump pressure port

Connect a 35000 kPa (5000 psi) pressure gauge to port (TP1) on the boom and hook control valve. The boom and hook control valve is located below the floorplate in the operator's compartment.

Start the engine and move the governor to the HIGH IDLE position. Move the hook control valve to the LOWER position. Document the values on both gauges.

Subtract the pressure in port (LS) from the pressure in port (TP1) . This is the margin pressure. The margin pressure should be 2100 ± 700 kPa (300 ± 100 psi) .

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Illustration 8	g00488510
Main hydraulic pump (1) Flow compensator spool

If the margin pressure is not correct, adjust the flow compensator spool to the correct pressure. Turn the nut clockwise in order to increase the pressure. Turn the nut counterclockwise in order to decrease the pressure. The flow compensator spool is located on the main hydraulic pump below the floorplate in the operator's compartment.

Cutoff Pressure

The cutoff pressure is the highest pressure that is produced by the hydraulic pump. Once this pressure is reached, the pump stalls and the output pressure will not rise. Perform the following test in order to ensure that the cutoff pressure is set accurately.

Remove the floorplate and disconnect the control levers. Remove the lever assembly.

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Illustration 9	g00488644
Combination valve (BR) Brake release port

Disconnect the brake release line from the combination valve on the hook winch motor. Plug port (BR) .

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Illustration 10	g00488504
Boom and hook control valve (TP1) Pump pressure port

Connect a 40000 kPa (6000 psi) pressure gauge to port (TP1) on the boom and hook control valve. The boom and hook control valve is located below the floorplate in the operator's compartment.

Start the engine and move the governor to the HIGH IDLE position. Move the hook control valve to the LOWER position. Measure the pressure on the gauge. This is the cutoff pressure for the pump. The pressure should be 30000 ± 700 kPa (4300 ± 100 psi) .

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Illustration 11	g00488652
Main hydraulic pump (1) Pressure compensator spool

If the cutoff pressure is not correct, adjust the pressure compensator spool to the correct pressure. Turn the nut clockwise in order to increase the pressure. Turn the nut counterclockwise in order to decrease the pressure. The pressure compensator spool is located on the main hydraulic pump below the floorplate in the operator's compartment.

Testing and Adjusting the Boom and Hook Control Valve

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Illustration 12	g00488813
Boom and hook control valve (1) Manifold (2) Relief valve (3) Two-way pilot control valve (4) Three-way pilot control valve (5) Pressure reducing valve (6) Check valve (7) Shuttle valve (8) Shuttle valve (9) Shuttle valve (10) Hook control valve (11) Boom control valve (12) Return manifold (TP1) Test port (pump pressure) (TP2) Test port (pilot pressure) (TP3) Test port (accumulator) (TP4) Test port (valve opening pressure)

The boom and hook control valve controls the operation of the boom and hook winches. The boom and hook control valve is located below the floorplate in the operator's compartment. Perform the following procedures in order to ensure that the components of the boom and hook control valve are set correctly.

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Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine.

To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.

Move the machine to a smooth horizontal location. Move away from working machines and personnel. Lower the boom to the ground.

Allow only one operator on the machine. Keep all other personnel away from the machine or in the view of the operator.

Engage the parking brake.

Stop the engine.

Move the control levers for the hydraulic system to all of the positions in order to release the pressure in the hydraulic system.

Carefully loosen the filler cap on the hydraulic tank in order to release the pressure in the tank.

Make sure that all of the hydraulic pressure is released before any fittings, hoses or components are loosened.

Tighten the filler cap on the hydraulic tank.

Make sure that the oil temperature is within the acceptable limits before removing lines or components.

Perform the procedure to discharge the hydraulic accumulator.

The pressure in the system has now been released and the lines and components can be removed.

Main Relief Valve

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Illustration 13	g00488925
Location of main relief valve

The main relief valve controls the maximum pressure that is allowed in the system. The main relief valve protects the hydraulic components from damage that is caused by high pressure spikes. The main relief valve is attached to the boom and hook control valve below the floorplate in the operator's compartment. Perform the following procedure in order to ensure that the main relief valve is set accurately.

Remove the floorplate and disconnect the control levers. Remove the lever assembly.

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Illustration 14	g00488652
Main hydraulic pump (1) Pressure compensator spool

Adjust the pressure compensator spool on the main hydraulic pump by two full turns clockwise in order to raise the cutoff pressure above the main relief pressure.

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Illustration 15	g00488644
Combination valve (BR) Brake release port

Disconnect the brake release line from the combination valve on the hook winch motor. Plug port (BR) .

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Illustration 16	g00488504
Boom and hook control valve (TP1) Pump pressure port

Connect a 40000 kPa (6000 psi) pressure gauge to port (TP1) on the boom and hook control valve.

Start the engine and move the governor to the HIGH IDLE position. Move the hook control valve to the LOWER position. Measure the pressure on the gauge. This is the main relief pressure setting. The pressure should be 33000 ± 700 kPa (4800 ± 100 psi) .

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Illustration 17	g00488927
Main relief valve (2) Adjustment screw

If the main relief pressure is not correct, adjust the pressure setting by turning adjustment screw (2) . Turn the screw clockwise in order to increase pressure. Turn the screw counterclockwise in order to decrease pressure. One full turn is approximately equal to 8070 kPa (1170 psi) .

After the main relief pressure is set correctly, adjust the pressure compensator spool to the original setting.

Pressure Reducing Valve (Pilot Circuit)

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Illustration 18	g00489571
Location of the pressure reducing valve (pilot circuit)

The pressure reducing valve for the pilot circuit reduces the pump pressure to a controllable level for the pilot control valves. The pressure reducing valve is located on the boom and hook control valve below the floorplate in the operator's compartment. Perform the following procedure to ensure that the pressure reducing valve for the pilot circuit is set accurately.

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Illustration 19	g00489660
Boom and hook control valve (TP2) Pilot pressure port

Connect a 10000 kPa (1450 psi) pressure gauge to port (TP2) .

Start the engine. Move the governor lever to the HIGH IDLE position.

Move the hook control valve to the LOWER position. Read the pressure on the gauge. The pressure should be approximately 5200 kPa (750 psi) .

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Illustration 20	g00489669
Pressure reducing valve (pilot circuit) (1) Adjustment screw

If the pilot pressure is not correct, adjust the pressure setting by turning adjustment screw (1) . Turn the screw clockwise in order to increase pressure. Turn the screw counterclockwise in order to decrease pressure. One full turn is approximately equal to 6000 kPa (870 psi) .

Testing and Adjusting the Load Sensing Manifold

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Illustration 21	g00475228
Load sensing manifold (1) Manifold (2) Shuttle valve (3) Three-way pilot control valve (4) Shuttle valve (5) Shuttle valve (6) Shuttle valve (a1) HOOK LOWER port (pilot pressure) (b1) HOOK RAISE port (pilot pressure) (A1) HOOK LOWER pressure port (B1) HOOK RAISE pressure port (A2) BOOM LOWER pressure port (B2) BOOM RAISE pressure port (LS) Load sensing port (DR) Drain port

The load sensing manifold is used in order to resolve the highest pressure that is required by either the boom or the hook winch. This pressure signal is sent to the load sensing port on the main hydraulic pump. The pump responds with the proper pressure in order to perform the task. The load sensing manifold is located below the guards on the right side of the operator's compartment. Perform the following procedure to ensure that the load sensing manifold is set accurately.

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Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine.

To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.

Move the machine to a smooth horizontal location. Move away from working machines and personnel. Lower the boom to the ground.

Allow only one operator on the machine. Keep all other personnel away from the machine or in the view of the operator.

Engage the parking brake.

Stop the engine.

Move the control levers for the hydraulic system to all of the positions in order to release the pressure in the hydraulic system.

Carefully loosen the filler cap on the hydraulic tank in order to release the pressure in the tank.

Make sure that all of the hydraulic pressure is released before any fittings, hoses or components are loosened.

Tighten the filler cap on the hydraulic tank.

Make sure that the oil temperature is within the acceptable limits before removing lines or components.

Perform the procedure to discharge the hydraulic accumulator.

The pressure in the system has now been released and the lines and components can be removed.

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Illustration 22	g00489807
Load sensing manifold (1) Three-way pilot control valve (a1) HOOK LOWER port (pilot pressure) (LS) Load sensing port

Connect a 965 kPa (140 psi) pressure gauge to the HOOK LOWER pilot line that is connected to the load sensing manifold.

Install a 9650 kPa (1400 psi) in the load sensing line that connects the load sensing manifold to the hydraulic pump.

Start the engine. Move the governor to the HIGH IDLE position.

Slowly move the hook control valve toward the LOWER position. Move the control valve for a small distance and check the pressure in the load sensing line. When the gauge in the load sensing line begins to read a pressure, record the pressure in the HOOK LOWER pilot line. The pressure should be approximately 620 kPa (90 psi) .

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Illustration 23	g00489810
Three-way pilot control valve (2) Adjustment screw

If the pressure is not correct, adjust three-way pilot control valve (1) by turning adjustment screw (2) . Turn the screw clockwise in order to increase pressure. Turn the screw counterclockwise in order to decrease pressure. One full turn is approximately equal to 520 kPa (75 psi) .

Testing and Adjusting the Combination Valves

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Illustration 24	g00489818
Combination valves for the hook (left) and the boom (right) (1) Manifold (2) Directional valve (3) Pressure reducing valve (4) Counterbalance valve (BR) Brake release port (DR) Drain port

Combination valves are mounted to the boom and hook winch motors. These valves perform two functions. First, the combination valves reduce pressure to the brake release ports on the winches. The combination valves also control the back pressure in the winch motors when the implements are lowered. Perform the following procedures to ensure that the components of the combination valves are set accurately.

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Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine.

To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.

Move the machine to a smooth horizontal location. Move away from working machines and personnel. Lower the boom to the ground.

Allow only one operator on the machine. Keep all other personnel away from the machine or in the view of the operator.

Engage the parking brake.

Stop the engine.

Move the control levers for the hydraulic system to all of the positions in order to release the pressure in the hydraulic system.

Carefully loosen the filler cap on the hydraulic tank in order to release the pressure in the tank.

Make sure that all of the hydraulic pressure is released before any fittings, hoses or components are loosened.

Tighten the filler cap on the hydraulic tank.

Make sure that the oil temperature is within the acceptable limits before removing lines or components.

Perform the procedure to discharge the hydraulic accumulator.

The pressure in the system has now been released and the lines and components can be removed.

Testing and Adjusting the Brake Release Pressures

Note: The same procedure is used for the boom and the hook winch.

Connect a 16000 kPa (2300 psi) pressure gauge to port (BR) on the combination valve.

Start the engine. Move the governor control lever to the HIGH IDLE position.

Move the hook control valve to the LOWER position. Record the pressure on the gauge. This is the brake release pressure. The pressure should be approximately 8600 kPa (1250 psi) .

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Illustration 25	g00489845
Pressure reducing valve (5) Adjustment screw

If the pressure is not correct, adjust the pressure by turning adjustment screw (5) . Turn the screw clockwise in order to increase pressure. Turn the screw counterclockwise in order to decrease pressure. One full turn is approximately equal to 6000 kPa (870 psi) .

Testing and Adjusting the Counterbalance valves

Note: The same procedure is used for the boom and the hook winch.

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Illustration 26	g00526363
(6) HOOK LOWER pressure tap

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Illustration 27	g00526535
(7) BOOM LOWER pressure tap

Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (6) for the hook and pressure tap (7) for the boom.

Start the engine. Move the governor control lever to the HIGH IDLE position.

Remove any load from the hook. Move the hook control lever to the LOWER position. Record the pressure on the gauge.
Note: Use the boom control lever when you are checking the boom circuit.

The result should be approximately 22800 kPa (3300 psi) for the hook winch circuit. The result should be approximately 14500 kPa (2100 psi) for the boom circuit.

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Illustration 28	g00489922
Counterbalance valve (8) Adjustment screw

If the counterbalance valve is not set correctly, adjust the valve by turning adjustment screw (8) . Turn the screw counterclockwise in order to increase pressure. Turn the screw clockwise in order to decrease pressure. One full turn is approximately equal to 6900 kPa (1000 psi) .

Boom Kickout Valve Adjustment

Remove the cover plate from the left pipelayer frame.

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Illustration 29	g00489980
Boom kickout valve (1) Valve (2) Plunger (3) Left pipelayer frame (4) Bolts (A) 12.979 cm (5.11 inch)

Loosen bolts (4) that mount valve (1) to the frame. Valve (1) should be able to move freely through slotted holes in the mounting bracket.

Adjust valve (1) so that dimension (A) is 12.979 cm (5.11 inch). This is the distance between the roller on valve (1) and plunger (2) .

Tighten bolts (4) .

Start the engine. Set the governor control lever in the LOW IDLE position.

Slowly raise the boom. When the boom is vertical, the crossmember on the boom should be in contact with the plunger. The plunger will actuate the boom kickout valve and the motor should stop.

If the winch motor does not stop, repeat the procedure above. Move valve (1) by2 mm (0.0787 inch) closer to plunger (2) .

Testing and Adjusting the Counterweight Relief Valve

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Illustration 30	g00490326
Counterweight

Extend the counterweight.

Stop the engine.

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Illustration 31	g00425021
Counterweight control lever (1) EXTEND (2) HOLD (3) RETRACT

Move the counterweight control lever to all three positions in order to release the pressure in the counterweight hydraulic circuit.

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Illustration 32	g00490328
Pressure tap for the counterweight hydraulic circuit

Attach a 40000 kPa (5800 psi) pressure gauge to the pressure tap for the counterweight hydraulic circuit. This pressure tap is located behind the access panel to right of the operator's seat.

Start the engine again and move the counterweight control lever to the EXTEND position. Record the pressure on the pressure gauge. This is the relief valve pressure setting. This pressure should be approximately 12400 kPa (1800 psi) .

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Illustration 33	g00490339
Counterweight control valve (bottom view) (1) Adjustment screw

If the pressure is not correct, adjust adjustment screw (1) on the counterweight relief valve. Turn the screw clockwise in order to increase pressure. Turn the screw counterclockwise in order to decrease pressure.