559D and 579D Knuckleboom Loaders Caterpillar

Relief Valve (Line) - Test and Adjust

Usage:

559D KL5

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Illustration 1	g03322248
Front view of main control valve (LS) Left control valve controlling oil from rear pump (Left side as viewed sitting in the operator seat) (RS) Right control valve controlling oil from front pump (Right side as viewed sitting in the operator seat) (MR) Main relief valve (R1) Stick UP/OUT relief valve (R2) Grapple CLOSE relief valve (R3) Boom UP relief valve (R4) Bypass 1 relief valve (R5) Grapple Rotate RIGHT relief valve

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Illustration 2	g03322249
Rear view of the main control valve (LS) Left control valve controlling oil from rear pump (Left side as viewed sitting in the operator seat) (RS) Right control valve controlling oil from front pump (Right side as viewed sitting in the operator seat) (R6) Bypass 2 relief valve (R7) Stick DOWN/IN relief valve (R8) Grapple Rotate LEFT relief valve (R9) Grapple OPEN relief valve (R10) Boom DOWN relief valve

Specifications

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Table 1
Line Relief Valve Pressures
Implement	Function	Engine RPM	Hydraulic Pump	Specification	Actual
Main Boom	Up	1800	Front	25855 ± 345 kPa (3750 ± 50 psi)
	Down	1800	Front	12273 ± 345 kPa (1780 ± 50 psi)⁽¹⁾
	Down	1800	Front	13376 ± 345 kPa (1940 ± 50 psi)⁽²⁾
Stick Boom	Up/Out	1800	Rear	31026 ± 345 kPa (4500 ± 50 psi)
Stick Boom	In/Down	1800	Rear	31026 ± 345 kPa (4500 ± 50 psi)
Swing	Left	1800	Rear	25897 ± 262 kPa (3756 ± 38 psi)
Swing	Right	1800	Rear	25897 ± 262 kPa (3756 ± 38 psi)
Grapple	Open	1800	Front	34475 ± 3450 kPa (5000 ± 50 psi)
Grapple	Close	1800	Front	34475 ± 3450 kPa (5000 ± 50 psi)
Grapple Rotate	Left	1800	Rear	11030 ± 345 kPa (1600 ± 50 psi)
Grapple Rotate	Right	1800	Rear	11030 ± 345 kPa (1600 ± 50 psi)

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⁽¹⁾	For 559D and 2384D machines
⁽²⁾	For 579D and 2484D machines

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Table 2
Port Relief Adjustment Values
Turns	PSI Value
1/6 (one Flat)	3300 kPa (478 psi)
2/6 (two Flats)	6600 kPa (956 psi)

The following test procedures outline the steps that are required to test and adjust the individual line relief valves. Because most of the functions have relief valve settings above the main relief setting, the main relief pressure must be raised to perform these tests. For this reason, these tests should be performed first.

In this test procedure, the main boom "Up" is used to increase the main relief setting. The line reliefs will be set starting with the highest setting, and working to the lesser settings.

Note: The main relief valve MUST be returned to specification when testing is complete and before the machine is placed back into service.

The pressure test ports for these tests are on the underside the hydraulic pumps. The relief valves are on the main hydraulic valve by the corresponding pilot valves.

Note: The hydraulic oil temperature must be at 60° ± 3°C (140° ± 5°F) or higher to perform this test.

Note: Refer to Illustration 1, Illustration 2, and Table 1, for relief valve locations and pressure specifications.

Note: When adjusting relief valves to a lower setting, reduce the pressure below specification, then slowly raise to specification.

Required Tools

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Illustration 3	g02571852
Tooling (A) 198-4240 Digital Pressure Indicator Gp

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Table 3
Required Tools
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

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⁽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.

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Table 4
Port Relief Adjustment Tools
Adjustment Fastener	Tool
Locknut	22-mm Wrench
Adjusting screw	6-mm Allen wrench
Cartridges	32-mm socket wrench

Test Preparation

The testing procedure requires two people.

Note: Use the information in the reference to prepare the machine for this test. Also, use the information in the reference to relieve any hydraulic pressure that may be in the hydraulic system.

Reference: For the correct procedure to prepare the machine for this test, refer to Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.

Reference: For the correct procedure to relieve any hydraulic oil pressure that may be in the hydraulic system, refer to Testing and Adjusting, "System Pressure - Release" for the machine that is being serviced.

If the hydraulic oil is below 60° ± 3°C (140° ± 5°F), start the engine and run the hydraulics until the engine is at operating temperature. Running the implement functions over the relief valve will aid in warming the hydraulic fluid.

Temporarily Increasing the Main Relief Valve for Testing

This procedure is necessary to test line relief pressures that are set higher than the main relief valve.

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Illustration 4	g03322669
Location of pump pressure ports (FP) Pressure test port for the front pump (RP) Pressure test port for the rear pump (PP) Pressure test port for the pilot pump

Ensure that the area around the machine is clear of danger and that the hydraulic oil is at operating temperature. With the engine "OFF", connect appropriate tooling (A) onto test port (FP). Tooling (A) must safely test 35200 kPa (5100 psi).
Locate Boom UP relief valve (R3). Loosen the locknut. Turn the adjusting screw IN (CW) until the screw is bottomed out. Back the adjusting screw OUT (CCW) one turn. Tighten the lock nut.
Locate main relief valve (MR). Start the engine and run the engine 1800 RPM.
Operate the boom UP function into a stall condition.
Loosen the locknut on main relief valve (MR). Turn the adjusting screw IN (CW) until the pressure on the gage reads 35200 kPa (5100 psi). Tighten the locknut.
Release the function and proceed to 5.

Grapple Open/Close

The grapple open relief valve and grapple close relief valve is set higher than the main relief. The main relief valve must be adjusted to perform this test. Refer to 4 to adjust the main relief valve.

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Illustration 5	g03322669
Location of pump pressure ports (FP) Pressure test port for the front pump (RP) Pressure test port for the rear pump (PP) Pressure test port for the pilot pump

Grapple Open

Install appropriate tooling (A) onto pressure port (FP) on the front hydraulic pump. Tooling (A) must safely check 34470 kPa (5000 psi).
Start the engine and warm the hydraulics to operating temperature. Operating temperature is 60° C (140° F).
Run the engine at 1800 RPM.
Have the operator engage the Grapple Open function to stall condition and hold. Observe the pressure reading at the BKR port relief. Release the function.
If the pressure is within specification, proceed to "Grapple Close".
If the pressure is not within specification, relief valve (R9) must be adjusted.
Use a 22-mm wrench for the lock nut and a 6-mm Allen wrench for the adjusting screw. Back off the lock nut. Turn the adjusting screw (CW) to increase the pressure reading, or turn the adjusting screw (CCW) to decrease the pressure reading.
Note: Use caution when adjusting the relief valve. Very little movement produces a great change in pressure.
When the setting is adjusted, tighten the locknut. Retest the function to ensure that the pressure is correct.
Proceed to "Stick Boom".

Grapple Close

Run the engine at 1800 RPM.
Have the operator engage the Grapple Close function to stall condition and hold. Observe the pressure reading at the AKR port relief. Release the function.
If the pressure is within specification, proceed to "Stick Boom""Stick Boom".
If the pressure is not within specification, relief valve (R9) must be adjusted.
Have the operator engage the Grapple Close function to stall condition and hold. Use a 22-mm wrench for the lock nut and a 6-mm Allen wrench for the adjusting screw. Back off the lock nut. Turn the adjusting screw (CW) to increase the pressure reading, or turn the adjusting screw (CCW) to decrease the pressure reading.
Note: Use caution when adjusting the relief valve. Very little movement produces a great change in pressure.
When the setting is adjusted, tighten the locknut. Release the function. Retest the function to ensure that the pressure is correct.
Proceed to "Stick Boom".

Stick Boom

Stick Boom IN/DOWN

Install appropriate tooling (A) onto pressure port (RP) on the rear hydraulic pump. Tooling (A) must safely test 31000 kPa (4500 psi).
Ensure that the clearance around the loader is sufficient to cycle the boom. Ensure that the engine is at operating temperature. Start the engine and run the engine at 1800 RPM.
Engage the Stick Boom IN/DOWN function until the cylinder is bottomed out, and hold. Observe the pressure reading at the BAR port relief, then release the function.
If the pressure for the Stick Boom IN/DOWN is within specification, proceed to "Stick Boom IN/DOWN".
If the pressure for the Stick Boom IN/DOWN is not within specification, relief valve (R7) must be adjusted.
Gain access to relief valve (R7) for Stick Boom IN/DOWN. Return the Stick Boom IN/DOWN function to the stall condition.
Insert a 6-mm Allen wrench into the adjusting screw. Back off the lock nut. Turn the adjusting screw (CW) to increase the pressure reading, or turn the adjusting screw (CCW) to decrease the pressure reading. When the pressure is adjusted to specification, tighten the locknut. Release the function and proceed to "Stick Boom UP/OUT".
Note: If the adjustment for the Stick Boom cannot be adjusted to specification, the minimum displacement adjustment screw must be adjusted. Refer to Step 5 through Step 6.c for this procedure.
1. Release all functions and shutdown the machine.
2. Gain access to minimum adjustment screw (MD) for the rear pump.
3. Loosen the locknut. Turn adjustment screw (MD) IN (CW) one eighth (1/8) of a turn. Tighten the locknut.
  Note: Do not turn screw (MD) over 1/8 turn per check. Very little movement may produce a great change.
4. Start the machine. Repeat Step 3 and Step 4 to adjust the relief valve adjustment.
5. Repeat the minimum displacement adjustment until the relief for the Stick Boom IN/DOWN is set to specification.
Stall the function again to double check the new setting. Release the function.
Proceed to "Stick Boom UP/OUT".

Stick Boom UP/OUT

Ensure that the appropriate tooling (A) is installed onto pressure port (RP) on the rear hydraulic pump. Tooling (A) must safely test 31000 kPa (4500 psi).
Ensure that the clearance around the loader is sufficient to cycle the boom. Ensure that the engine is at operating temperature. Start the engine and run the engine at 1800 RPM.
Engage the Stick Boom UP/OUT function until the cylinder is bottomed out, and hold. Observe the pressure reading at the AAR port relief, then release the function.
If the pressure for the Stick Boom UP/OUT is within specification, proceed to "Main Boom UP".
If the pressure for the Stick Boom UP/OUT is not within specification, relief valve (R1) must be adjusted.
Gain access to relief valve (R1) for Stick Boom UP/OUT. Return the Stick Boom IN/DOWN function to the stall condition.
Insert a 6-mm Allen wrench into the adjusting screw. Back off the lock nut. Turn the adjusting screw (CW) to increase the pressure reading, or turn the adjusting screw (CCW) to decrease the pressure reading. When the pressure is adjusted to specification, tighten the locknut, and release the function.
Stall the function again to double check the new setting. Release the function.
Proceed to "Main Boom UP".

Main Boom UP

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Illustration 7	g03322669
Location of pump pressure ports (FP) Pressure test port for the front pump (RP) Pressure test port for the rear pump (PP) Pressure test port for the pilot pump

Install appropriate tooling (A) onto pressure port (FP) on the front hydraulic pump. Tooling (A) must safely test 27600 kPa (4000 psi).
Ensure that the clearance around the loader is sufficient to cycle the boom. Ensure that the engine is at operating temperature. Start the engine and run the engine at 1800 RPM.
Engage the main boom UP function until the cylinders are bottomed out, and hold. Observe the pressure reading at the ABR port relief,. Release the function.
If the pressure reading is correct, proceed to Step 5. If the reading is not to specification, relief valve (R3) must be adjusted.
Return the function to stall condition. Use a 22-mm wrench for the lock nut and a 6-mm Allen wrench for the adjusting screw. Back off the lock nut. Turn the adjusting screw (CW) to increase the pressure reading, or turn the adjusting screw (CCW) to decrease the pressure reading.
Note: Use caution when adjusting the relief valve. Very little movement produces a great change in pressure.
When the setting is to specification, tighten the locknut. Release the function. Repeat this test to ensure that the pressure setting is still correct.
If no further tests are planned, proceed to "Returning Main Relief Back to Specification". Otherwise, proceed to "Swing Drive (Piston Motor)".

Swing Drive (Piston Motor)

This test must be performed while the main relief is still set temporarily higher. When this test is complete, proceed to "Returning Main Relief Back to Specification".

The pressure ports for this test are on the piston motor.

Refer to Testing and Adjusting, "Piston Motor (Swing Drive) Relief Valve Pressure - Test and Adjust" for this procedure.

Returning Main Relief Back to Specification

Install appropriate tooling (A) onto pressure port (FP) on the front hydraulic pump. Tooling (A) must safely test 41400 kPa (6000 psi).
Ensure that the clearance around the loader is sufficient to cycle the boom. Ensure that the engine is at operating temperature. Start the engine and run the engine at 1800 RPM.
Locate main relief valve (MR).
Engage the grapple Close function until the cylinder is bottomed out, and hold (stall condition).
Loosen the locknut. Slowly lower the relief pressure below main relief specification.
Relief pressure specification f is 24995 ± 345 kPa (3625 ± 50 psi).
Note: Use caution when adjusting the relief valve. Very little movement produces a great change in pressure.
Tighten the locknut. Release the functions.
Repeat the check to double check the main relief setting.
Proceed to "Main Boom Down".

Main Boom Down

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Illustration 8	g03322669
Location of pump pressure ports (FP) Pressure test port for the front pump (RP) Pressure test port for the rear pump (PP) Pressure test port for the pilot pump

Install tooling (A) onto pressure port (FP) on the front hydraulic pump. Tooling (A) must safely test 13800 kPa (2000 psi).
Ensure that the clearance around the loader is sufficient to cycle the boom. Ensure that the engine is at operating temperature. Start the engine and run the engine at 1800 RPM.
Fully extend the stick boom. Engage the Main Boom Down and the Grapple Close functions and hold the functions.
Observe the gauge reading at the BBR port relief. Release the control.
If the pressure reading is correct, proceed to Step 7. If the reading is not to specification, relief valve (R10) must be adjusted.
Return the function to stall condition. Use a 22-mm wrench for the lock nut and a 6-mm Allen wrench for the adjusting screw. Back off the lock nut. Turn the adjusting screw (CW) to increase the pressure reading, or turn the adjusting screw (CCW) to decrease the pressure reading.
Note: Use caution when adjusting the relief valve. Very little movement produces a great change in pressure.
When the setting is to specification, tighten the locknut. Release the function.
Repeat this test to ensure that the pressure setting is still correct.
If no further tests are planned, shut down the machine and relieve the pressure in the circuit. Remove test equipment. Otherwise, proceed to "Grapple Rotate".

Grapple Rotate

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Illustration 9	g03322669
Location of pump pressure ports (FP) Pressure test port for the front pump (RP) Pressure test port for the rear pump (PP) Pressure test port for the pilot pump

Install tooling (A) onto pressure port (RP) on the rear hydraulic pump.
Secure the grapple so the grapple will not rotate. Disconnect and cap the grapple rotate hydraulic lines. Plug and cap all exposed ports and lines.
Start the engine. Ensure that the engine is at operating temperature. Run the engine at high idle. Engage the "Grapple Rotate" function "LEFT".
Observe the pressure reading at the BOR relief port. If the pressure reading is correct, release the function and proceed to Step 5. If the reading is not to specification, relief valve (R8) must be adjusted.
Use a 22-mm wrench for the lock nut and a 6-mm Allen wrench for the adjusting screw. Back off the lock nut. Turn the adjusting screw (CW) to increase the pressure reading, or turn the adjusting screw (CCW) to decrease the pressure reading.
Note: Use caution when adjusting the relief valve. Very little movement produces a great change in pressure.
When the setting is to specification, tighten the locknut and release the function. Repeat Steps 1, 2, and3 to ensure that the pressure setting is still correct. Proceed to Step 5.
Ensure that the grapple is secure and will not rotate. Start the engine and run the engine at high idle. Engage the "Grapple Rotate" function "RIGHT".
Observe the pressure reading at the AOR relief port. If the pressure is within specification, release the function and skip to Step 9. If the reading is not to specification, relief valve (R5) must be adjusted.
Use a 22-mm wrench for the lock nut and a 6-mm Allen wrench for the adjusting screw. Back off the lock nut. Turn the adjusting screw (CW) to increase the pressure reading, or turn the adjusting screw (CCW) to decrease the pressure reading.
Note: Use caution when adjusting the relief valve. Very little movement produces a great change in pressure.
When the setting is to specification, tighten the locknut and release the function. Repeat this test to ensure that the pressure setting is still correct.
If no further tests are planned, shut down the machine and relieve the pressure in the circuit. Remove test equipment.

Stick Boom (Port-O-Power Method)

The port relief for the Stick BoomIN/DOWNand the Stick BoomUP/OUTare higher than the main relief setting. The loader main relief cartridge cannot be adjusted high enough to check these functions.

The above named port reliefs can be checked using a high-volume Port-O-Power with the control valve in the Neutral position. The following procedures outline the steps that are needed to perform this test.

Note: Stick cylinder work lines must be disconnected to conduct this test.

Test Preparation

Fully extend the boom and set the grapple on the ground with the jaws open. Make certain that the boom cannot move while the stick cylinder work lines are disconnected.
Shut down the engine, but leave the electric power "ON". Move the joysticks in all directions to relieve pilot pressure.
Swing pilot shut-off lever UP to disengage pilot controls.
Turn off electric power and remove the key.
Purge air from the reservoir. Do not work on the hydraulic system if the oil temperature exceeds 49° C (120° F). Use CAUTION while disconnecting hydraulic hoses.
Proceed to "Stick Boom".

Stick Boom Down/In

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Illustration 10	g03325743
(SB) Stick Boom cylinder (Shown in raised position for clarity of location. This position is NOT TEST POSITION.)

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Illustration 11	g03325795
(SB) Stick Boom cylinder (Aa1) Hose connection to the rod end workport of the stick boom cylinder and "A" side of the valve (Ba1) Hose connection to the head (base) end workport of the stick boom cylinder and "B" side of the valve

Clean the area to be serviced. Gain access to the Stick Boom cylinder and disconnect work line (Aa1) leading to the rod end port.
Plug the open cylinder port and connect the Port-O-Power to the open work line.
Pressurize the Port-O-Power. Purge any air that is in the line. Stroke the Port-O-Power to check the port relief setting. The port relief should begin to relieve as the Port-O-Power gauge approaches 31000 kPa (4500 psi).
If the setting is not correct, adjust relief valve (R7). Gain access to relief valve (R7) for the Stick Boom Down/In function. Refer to Illustration 1 and 2 for the location of the relief valve.
Use a 22-mm wrench for the lock nut and a 6-mm Allen wrench for the adjusting screw. Back off the lock nut. Turn the adjusting screw in (CW) to increase the pressure reading, or turn the adjusting screw out (CCW) to decrease the pressure reading.
Note: Use caution when adjusting the relief valve. Very little movement produces a great change in pressure. Refer to Table 22for port relief adjustment values.
When the setting is to specification, tighten the lock nut. Open the Port-O-Power "Bleed Off" valve to remove residual pressure from the circuit.
Proceed to "Stick Boom UP/OUT".

Stick Boom Up/Out

Fluid is trapped in the "B" side of the circuit by the counterbalance valve. Therefore, the "B" port relief cartridge (R1) must be moved to the "A" port to perform this test. Take extreme care while removing the port relief from the "B" port side of this valve.

Thoroughly clean the area to be serviced. Remove the relief cartridge from the "A" port. Mark the cartridge and set the cartridge aside.
Remove the relief cartridge from the "B" port. Install the relief cartridge into the "A" port side.
Install the relief cartridge that was in the "A" port side into the "B" port side of the valve.
Pressurize the Port-O-Power. Purge any air that is in the line. Stroke the Port-O-Power to check the port relief setting. The port relief should begin to relieve as the Port-O-Power gauge approaches 31000 kPa (4500 psi).
If the setting is not correct, adjust relief valve (R1). Gain access to relief valve (R1) for the Stick Boom Down/In function.
Use a 22-mm wrench for the lock nut and a 6-mm Allen wrench for the adjusting screw. Back off the lock nut. Turn the adjusting screw in (CW) to increase the pressure reading, or turn the adjusting screw out (CCW) to decrease the pressure reading.
Note: Use caution when adjusting the relief valve. Very little movement produces a great change in pressure. Refer to Table2 for port relief adjustment values.
When the setting is to specification, tighten the lock nut. Open the Port-O-Power "Bleed Off" valve to remove residual pressure from the circuit.
Remove the Port-O-Power and connect the work line back into the cylinder port line.
When the test is complete, start the engine and test for leaks.