416B Hyd Test & Adjusting

416B Backhoe Loader 8ZK00001-05999 (MACHINE) POWERED BY 3054 Engin... Página 1 de 26

Shutdown SIS

Previous Screen Product: BACKHOE LOADER Model: 416B BACKHOE LOADER 8ZK Configuration: 416B Backhoe Loader 8ZK00001-05999 (MACHINE) POWERED BY 3054 Engine

Testing and Adjusting 416B, 426B, 428B, 436B, & 438B BACKHOE LOADERS HYDRAULIC SYS Media Number -SENR5808-01

Publication Date -17/05/1994

Date Updated -12/10/2001

Testing And Adjusting

Introduction Reference: For Specifications with illustrations, make reference to SENR5825, 416B, 426B, 428B, 436B & 438B Backhoe Loaders Hydraulic Systems Specifications. If the Specifications in SENR5825 are not the same as in the Systems Operation and the Testing and Adjusting, look at the printing date on the cover of each book. Use the Specification in the book with the latest date. NOTE: This book has been completely changed from the previous issue.

Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, do the procedure that follows before testing and adjusting the hydraulic system.

Do not check for leaks with your hands. Pin hole (very small) leaks can result in a high velocity oil stream that will be invisible close to the hose. This oil can penetrate the skin and cause personal injury. Use cardboard or paper to locate pin hole leaks. 1. Move the machine to a smooth horizontal location. Move away from working machines and personnel and lower the buckets or implements (loader and backhoe) and stabilizers to the ground. 2. Permit only one operator on the machine. Keep all other personnel either away from the machine or in view of the operator. 3. Engage the parking brake. 4. Stop the engine. 5. Move the hydraulic control levers to all positions to release the pressure in the hydraulic system. 6. Carefully loosen the filler cap on the hydraulic tank to release the pressure in the tank. 7. Make sure all hydraulic pressure is released before any fitting, hose or component is loosened, tightened,

05/04/2013


removed or adjusted. 8. Tighten the filler cap on the hydraulic tank. 9. The pressure in the system has now been released and lines or components can be removed. When defining a hydraulic system problem, the following procedure should be followed. First, do Visual Checks. If, when complete, the problem has not been identified, do Operational Checks. If the problem is still not fully understood, do Instrument Tests. This procedure will help identify hydraulic system problems. As soon as the problem is defined, go to Troubleshooting. The Troubleshooting section will list the probable causes of a known problem. Since there may be more than one cause for a problem, the Troubleshooting section may suggest specific inspections or instrument tests be done. These inspections and tests will help identify which of the causes is most probable. During a diagnosis of the hydraulic system, remember that correct oil flow and pressure are necessary for correct operation. Oil pressure is caused by resistance to the flow of oil.

Visual Checks Make reference to WARNING on the first page of the Testing And Adjusting section. A visual inspection of the hydraulic system and its components is the first step when identifying a problem. Stop the engine, lower the implements and stabilizers to the ground. To remove the tank filler cap, slowly turn the filler cap until it is loose. If oil comes out, let the tank pressure lower before the filler cap is removed. Make the following inspections: 1. Check all backhoe, stabilizer and loader oil line connections for damage and leaks. 2. Follow all backhoe, stabilizer and loader oil lines from the implement connections to valve connections. Check the lines and connections for damage and leaks. 3. Check the control valves for leaks. Look around the relief valves and the primary and secondary resolvers. 4. Check the pump and connections for damage and leaks. 5. Follow the pump lines to the tank and valves. Check the lines for damage and leaks. 6. Check the oil cooler and tank for damage and leaks. 7. Check tank oil level. 8. Use a clear bottle or container to get an oil sample from the tank immediately after the machine is stopped. Check for air bubbles in the oil sample. 9. Remove the filter element and check for particles removed from the oil by the filter element. A magnet will separate ferrous particles from nonferrous particles (piston rings, O-rings, seals, etc.).

Performance Tests 1. The temperature of the oil is too hot. 2. Pump makes unusual noise, the cylinders do not move smoothly.

05/04/2013


3. Large amount of air in the oil. 4. Pump pressure too low. 5. Pump pressure too high. 6. Pause before pressure is reached in all circuits. 7. Signal pressure not zero (or tank pressure) when all valves in HOLD and steering not used. 8. Any implement moves with control lever in HOLD position. 9. Line reliefs too noisy. 10. Too much implement drift. 11. Implement droops when going from a partially raised position to a raised position. 12. All cycle times too slow. 13. The backhoe boom, bucket or stick cycle times too slow. 14. There is too long of a pause at ground level before raising machine during boom lower cycle time check. 15. The backhoe boom, bucket or stick cycle times too fast. 16. The loader lift, tilt or clam, or the backhoe extendible stick or auxiliary cycle times are too slow. 17. The loader lift, tilt or clam, or the backhoe extendible stick or auxiliary cycle times are too fast. 18. Swing cycle times too slow. 19. Swing cycle times too fast. 20. Stabilizer lower cycle time too fast. 21. Stabilizer cycle times too slow. 22. Stabilizers will not Raise. 23. Stabilizers are unstable (jerky) when raising (lowering the machine). 24. Backhoe bucket slows or stops in mid stroke. 25. Backhoe bucket hits the load (curl) stop hard. 26. The swing cylinders hit the swing stops hard. Problem 1: The temperature of the oil is too hot. Probable Cause: 1. The viscosity of the oil is wrong. 2. The pressure compensator spool valve opens at low oil pressure. 3. The pump has too much wear. 4. There is a restriction in an oil passage. 5. The load of the system is too high. 6. Oil aeration. 7. A restriction to the flow of cool air through the oil cooler if equipped. 8. The bypass valve on oil cooler is opened. 9. Outside air temperature is too hot. 10. Attachments are operated too long. Problem 2: Pump makes unusual noise, the cylinder rods do not move smoothly and there are air bubbles in the oil. Probable Cause: 1. The viscosity of the oil is wrong. 2. The relief valve opens at low oil pressure. 3. Loose connection of the oil line on the inlet side of pump. Oil aeration. 4. The pump has too much wear. Problem 3: A large amount of air in the oil. Probable Cause: 1. A leak in the oil line between the tank and the pump. 2. Failure to correctly bleed the hydraulic system after assembly, inspection or testing. 3. Relief valve constantly opens and closes.

05/04/2013


4. Leakage in and around cylinder seals. Problem 4: Pump pressure too low. Probable Cause: 1. Flow spool side of compensator valve set wrong (margin pressure low). 2. Flow spool spring broken. 3. Pump not upstroking (swashplate blocked or actuator spring broken). 4. Leak in signal network. 5. Low setting in pressure compensator. Problem 5: Pump pressure too high. Probable Cause: 1. Pressure spool side of compensator valve set wrong. 2. Pressure spool in compensator valve not moving (stuck). 3. Pump not destroking (actuator piston stuck or swashplate blocked). Problem 6: There is a pause before pressure is reached in all circuits. Probable Cause: Air in signal network. Problem 7: Signal pressure is not zero (or tank pressure) when all valves are in HOLD and steering not used. Probable Cause: 1. All controls not in HOLD. 2. Signal network not vented. Problem 8: Any implement moves with control lever in HOLD position. Probable Cause: 1. The control valve and valve spool have a large amount of wear. 2. A piston seal in a cylinder has a large amount of wear. 3. A leak in a connection between the control valve and the cylinders. 4. Makeup or line relief valves are open. Problem 9: Line reliefs too noisy. Probable Cause: 1. Affected relief valve set too low. 2. Springs in affected relief valve broken or fatigued. 3. Pressure spool side of compensator valve set too high. Problem 10: Too much implement drift. Probable Cause: 1. Leakage in and around the seals on the piston in the cylinder(s) affected. 2. Low setting of line relief. 3. Leakage past a line relief valve or makeup valve for the affected circuit.

05/04/2013


4. The spool in the main control valve is not correctly centered. This problem can be caused by a broken spring or sticky valve spool. 5. If the drift problem is in the stabilizer cylinders, the cause can be any of those above. In addition, the lock valve in the stabilizer affected may not be seated properly. Problem 11: Implement droops when going from a partially raised position to a raised position. Probable Cause: 1. Air in signal network. 2. Advanced signal passages in the control valve main spool blocked in the affected circuit. 3. The control valve compensator spool spring(s) may be broken or fatigued. 4. The load check valve could be stuck on boom, bucket or stick. Problem 12: All implement cycle times too slow. Probable Cause: 1. Blockage or leakage in signal network. 2. Margin pressure setting incorrect. 3. Pump not at full stroke. (Actuator piston stuck or swashplate blocked.) 4. Pump bad. Problem 13: The backhoe boom, bucket or stick cycle times are too slow. Probable Cause: 1. The control valve main spool is not fully shifted for the affected circuit. 2. Blocked or partially blocked load signal going to pump compensator valve or leakage in the signal network. 3. The affected circuit line relief setting is too low. 4. The affected circuit line relief or makeup valve is leaking. 5. Leaking in and around the affected cylinder(s) piston seals. 6. Pump not at full stroke. (Actuator piston stuck or swashplate blocked.) 7. Low pump margin pressure setting. 8. If the backhoe bucket cycle time is too slow it can be any of the above. In addition, the cylinder snubber orifice may be blocked or partially blocked. Problem 14: There is too long of a pause at ground level before raising machine during boom lower cycle time check. Probable Cause: The restrictor spool in the backhoe inlet manifold stays open. (Broken restrictor spool spring or restrictor spool sticking.) Problem 15: The backhoe boom, bucket or stick cycle times are too fast. Probable Cause: 1. Margin pressure set too high. 2. Engine high idle set too high. Problem 16: The loader lift or tilt, clam, or the backhoe extendible stick or auxiliary cycle times are too slow. Probable Cause:

05/04/2013


1. The control valve main spool is not fully shifted for the affected circuits. 2. Blocked or partially blocked load signal going to pump compensator valves or leakage in the signal network. 3. The affected circuit line relief setting is too low. 4. The affected circuit line relief valve is leaking. 5. Leaking in and around the affected cylinder(s) piston seals. 6. Broken flow control spring. 7. Pump not at full stroke. (Actuator piston stuck or swashplate blocked.) 8. Low pump margin pressure setting. Problem 17: The loader lift, tilt, clam, or the backhoe extendible stick or auxiliary cycle times are too fast. Probable Cause: Margin pressure set too high. Problem 18: Swing cycle times too slow. Probable Cause: 1. The control valve main spool is not fully shifted. 2. Blocked or partially blocked load signal going to pump compensator valve or leakage in the signal network. 3. Swing relief valve setting too low. 4. Swing relief valve leaking. 5. Leaking in and around the swing cylinder piston seals. 6. Broken flow control spring. 7. Pump not at full stroke. (Actuator piston stuck or swashplate blocked.) 8. Low pump margin pressure setting. Problem 19: Swing cycle times too fast. Probable Cause: The control valve compensator spool not limiting flow and pressure. Springs broken or fatigued. Problem 20: Stabilizer LOWER cycle time is too fast. Probable Cause: Pump margin pressure setting is too high. Problem 21: Stabilizer cycle times are too slow. Probable Cause: 1. The control valve main spool is not fully shifted. 2. Blocked or partially blocked load signal going to the pump compensator valve or leakage in the signal network. 3. Leaking in and around the affected cylinder piston seals. 4. Pump is not at full stroke. (Actuator piston stuck or swashplate is blocked.) 5. Low pump margin pressure setting. 6. Orifice check valve plugged. Problem 22: Stabilizers will not raise (lowers machine). Probable Cause:

05/04/2013


There is a hydraulic lock because the pilot signal passage to the lock valve is blocked. Problem 23: Stabilizers are unstable (jerky) when raising (lowering machine). Probable Cause: The rod end orifice check valves are broken, missing or installed backwards. Problem 24: Backhoe bucket slows or stops in mid stroke. Probable Cause: Broken or missing snap ring on cylinder rod. The snubber piston is not held in place and may now work anywhere in the stroke. Problem 25: The swing cylinders hit the swing stops hard. Probable Cause: Broken head end snubber spring on affected cylinder.

Pump Efficiency Tests This test is designed to tell if a pump is operating within design parameters. Presently only a bench test is available. This test should be run only if all cylinder cycle times are too slow and the resolver network has checked out good. For any pump test, the pump flow, measured in U.S. gpm (liter/min) at 100 psi (690 kPa) will be larger than the pump flow at 1000 psi (6900 kPa) at the same rpm The difference between the pump flow of two operating pressures is the flow loss.

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

05/04/2013


If the percent of flow loss is more than 10%, pump performance is not good enough. *

Numbers in examples are for illustration and are not values for any specific pump or pump condition. See Specifications For 416B, 426B, 428B, 436B, 438B Backhoe Loaders Hydraulic System, Form SENR5808, for pump flow of a new pump at 100 psi and 1000 psi.

Test on the Bench If the test bench can be run at 1000 psi and at full pump rpm, find the percent of flow loss using Formula I.

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

Operation Checks Make reference to WARNING on the first page of the Testing And Adjusting section.

05/04/2013


The operation checks can be used to find leakage in the system. They can be used to find a bad valve or pump. The speed of rod movement when the cylinders operate can be used to check the condition of the cylinders and the pump. Lift, lower, dump and tilt back the loader bucket several times. Operate each backhoe implement function several times. Lower and raise the stabilizer several times. 1. Watch the cylinders as they are extended and retracted. Movement must be smooth and regular. 2. Listen for noise from the pump. 3. Listen for the sound of the relief valves. They must not open except when the cylinders are fully extended or retracted, when the bucket is empty. 4. Watch the operation of the return to dig features. The loader lift control lever has a detent in the FLOAT position. The loader bucket tilt control lever has a detent in the TILT BACK position (only when the bucket is between full dump and the bucket angle to dig).

Implement and Stabilizer Cylinders Drift Check The drift rates will change with different conditions of the hydraulic components as well as with the operation, the type of bucket (empty or loaded), hydraulic oil temperature, etc. The values shown are for an empty bucket. Before measuring drift on the implements, the cylinders must be extended at least five times. Check the oil temperature. To check the loader lift circuit, lift the bucket to maximum height and move the lift control lever to the HOLD position. Measure the distance (and check the time) that the lift cylinders retract. Compare to the chart. To check the loader tilt circuit, disconnect the bucket leveler. Lift the bucket to 800 to 1000 mm (31.5 to 39.5 in). Tilt the bucket until it is level. Move the control lever to HOLD. Measure the distance (and check the time) that the tilt cylinder retracts. Compare to the chart.

To check the backhoe boom, bucket and stick cylinders, position implements in the following manner.

05/04/2013

416B Backhoe Loader 8ZK00001-05999 (MACHINE) POWERED BY 3054 En...

Página 10 de 26

Position stick horizontal (parallel) to ground. Position the bucket so the bottom (cutting edge) is perpendicular to the ground. If the machine has a factory installed extendible stick, it should be fully retracted. Raise the boom until it is 200 to 400 mm (8.0 to 15.5 in) from the ground. When correctly positioned, move implement control levels to HOLD. Measure the distance (and check the time).

To check stabilizer cylinder drift, position the backhoe loader as in loader circuit and backhoe circuit drift tests. Lower the stabilizer cylinders and lift the rear wheels about 50 mm (2.0 in) off the ground.

If the cylinder drift is too much: 1. Check the makeup valves or line relief valves in the affected control valves. 2. Check the condition of the valve spools in the affected control valves. 3. Check the piston seals in the cylinders.

Implement and Stabilizer Cylinders Speed Check Start and run the engine at high idle rpm. Increase oil temperature by operating each of the implements several times. During actual tests, leave the engine in high idle. The following tests should be run through full cylinder stroke.

05/04/2013


Página 11 de 26

05/04/2013


Página 12 de 26

05/04/2013


Página 13 de 26

The following tests should be run from a ground level implement to the fully raised position.

The following tests should be run from fully raised implement to ground level implement. During the tests, the implement may impact the ground heavily. Care should be taken to protect finished ground surfaces.

05/04/2013


Página 14 de 26

For the final two tests, position the boom at 45° from horizontal. Fully extend the stick and move the bucket to the fully loaded (closed or curled) position. If the extendible stick has been factory added, it should be fully retracted. Then move the boom control lever to full boom DOWN. Measure the time until the bucket hits the ground. To measure boom pause time, keep the control lever in boom DOWN position and measure the time from when the bucket hits the ground until the rear of the machine begins to raise.

If the travel times are not correct: 1. Check the setting of the relief valves. 2. Check the makeup or line relief valves in the affected control valves. 3. Check the valve spools in the affected control valves. 4. Check the piston seals in the cylinders. 5. Check resolver network. 6. Check low pressure standby and margin pressure. 7. Check the pump efficiency.

Signal Resolver Network Check A resolver is a check valve. It compares two pressures. The lower of the two pressures is blocked. The higher of the pressures or signals goes to the next component in the resolver network.

05/04/2013


Página 15 de 26

Typical Control Valve (1) Primary resolver. (2) Secondary resolver.

There are two resolvers per implement control valve. Primary resolver (1) compares rod to head cylinder pressures. Secondary resolver (2) compares the highest primary signal in its control valve to the highest primary signal in the next control valve. The secondary resolvers are arranged in series leading to the pump compensator valve. The primary and secondary resolvers can be affected by debris, cut or missing seals, bad resolver seats, or missing balls.

Signal Resolver Network Troubleshooting The signal network can be easily checked. Start the engine and warm up the hydraulic oil. Run the engine at LOW IDLE for this check. Connect a 30 000 kPa (4000 psi) gauge to the signal line pressure tap. Operate each control lever in the following order: 1. Left stabilizer. 2. Right stabilizer. 3. Boom. 4. Swing. 5. Backhoe bucket. 6. Stick. 7. Extendible stick (if equipped). 8. Loader lift. 9. Loader bucket tilt. 10. Multi-purpose bucket (if equipped). 11. Steering. Work each implement against a load. Watch the gauge. Maximum system pressure should be seen for all circuits. By using the gauge, small leakage problems such as cut or missing seals can be detected.

Secondary Resolvers (Two or More Valve Sections) If two or more control valves in series next to each other fail to work normally, the problem may be in the secondary resolver of the first implement control valve that is closer to pump supply that does work properly. This control valve's secondary resolver is allowing signal pressure from any control valve further from pump supply to leak through to either the rod or head end signal passage of that control valve to tank. This leakage may be caused by a ball not seating against the drain side of its resolver causing the valve to not function properly. This holds true unless; the ball is missing; there is debris preventing the ball from seating properly; the seal is missing or leaking when multiple valves malfunction. Operate the malfunctioning valve farthest from the pump and at the same time start going through the previously mentioned valve order. The first valve that makes both of the implements work, is the one with the bad secondary resolver. What is happening is that the farthest valve is sending a signal and the valve with a bad seal or missing ball is also sending a signal. When both signals meet at the valve with the bad secondary resolver the leak has no impact on the signal that now goes to the pump and it has no effect on the flow control valve.

05/04/2013


Página 16 de 26

Primary Versus Secondary Resolver For valves with a flow control spool, if only one valve section either fails to work in one or both directions or works slowly in one or both directions, the primary or secondary resolver in that control valve may be bad. To determine which secondary resolver is bad perform the following check. Stall an implement further away from the pump than the valve in question. This will force the ball in the secondary resolver to seat away from the drain side of the resolver. This eliminates the possibility of a leak on the drain side of the secondary resolver. Now operate the suspect valve while holding the other implement in stall. If it is still operating slow in one or both directions, then the primary resolver may be bad. If the primary resolver is bad, then the pressure bleed off caused by the bad resolver is affecting the operation of the flow control spool (if so equipped) in the valve body. The effective force (signal pressure + spring) trying to open up the valve to allow flow to the cylinder is insufficient to meet the cylinder load requirement so the implement has a slower response. Normally if an implement is slow in both directions, the problem is usually in the secondary resolver. If an implement is slow in one direction it is typically caused by a bad primary resolver (caused by debris or bad seals). Other causes of malfunctioning valve sections might be a misadjusted linkage, a broken pressure reducing valve spring, the flow control spool incorrectly installed or bad line relief and/or makeup valves. NOTE: If there is debris in the system. It is recommended that the system be flushed by removing all the balls in the secondary resolvers and operate the implements. Enough flow will be supplied to flush the debris to the tank.

Location of Pressure Taps Make reference to the WARNING on the first page of Testing And Adjusting section. Instrument testing on the hydraulic system and its components is the final step when diagnosing a problem. Test results should verify the status of a component. Adjusting procedures are provided where needed.

Hydraulic Pump (front) (1) System pressure tap. (2) Compensator valve.

05/04/2013


Página 17 de 26

Hydraulic Pump (right side) (3) Signal pressure tap.

Hydraulic Oil Contamination Test Make reference to the WARNING on the first page of Testing And Adjusting section. The hydraulic oil in this system is SAE 10W. If the oil becomes dirty, component failure could result. Dirty oil can also contribute to overheating. Start the engine and run at high engine rpm. Actuate all cylinders through at least ten full strokes (do not use loader float for this procedure). Lower all implements and stabilizers to the ground. Stop the engine. Move all control levers through all positions to release pressure in the hydraulic system. Remove the tank filler cap slowly. If oil or pressure is seen or heard coming out, let the tank pressure lower before the cap is fully removed. Connect a hose assembled to system pressure quick disconnect (1) in the pump discharge port. Run the free end of the hose into the tank through the fill tube. Make sure all hydraulic controls are in HOLD. Start the engine and run at low idle. NOTE: Do not operate hydraulic controls. Draw a 50 mL sample through a tee in the hose assembly. The contaminant level must be equal to or less than the following:

Hydraulic Pump Make reference to the WARNING on the first page of Testing And Adjusting section.

05/04/2013


Página 18 de 26

Pump discharge pressures are known values and can be tested during two specific conditions. These two conditions are low pressure standby and high pressure stall.

Low Pressure Standby Test Procedure 1. Lower all implements and stabilizers to the ground. 2. Install a 0 to 4000 kPa (0 to 580 psi) gauge in pump discharge pressure tap (1). 3. Start the engine and run at high idle rpm. 4. Leave all control levers in HOLD. 5. Do not move the steering wheel. 6. The pressure reading must be about 2200 ± 100 kPa (320 ± 15 psi). Low pressure standby pressure is equal to margin pressure 2100 ± 100 kPa (305 ± 15 psi) plus the additional pressure needed to keep the pump swashplate at the angle needed to maintain leakage flow. This is about an additional 10 kPa (15 psi). 7. Adjustments to pump output should not be made based on the results of this test. Instead, if the results are not acceptable, the Margin Pressure Test should be run.

High Pressure Stall Test Procedure 1. Lower all implements and stabilizers to the ground. 2. Stop the engine and move the control levers to all positions to release system pressure. 3. Install a 0 to 25 000 kPa (0 to 3600 psi) gauge in pump discharge pressure tap (1). 4. Start the engine and run at high idle rpm. 5. Move all control levers (one at a time) except boom down in both directions to initiate a stall condition. 6. All pressure readings must be 20 700 ± 350 kPa (3000 ± 50 psi). If the pressure readings are all too low or too high, the pressure spool in the compensator valve needs to be adjusted. See Compensator Valve Adjustment.

Margin Pressure Test

05/04/2013


Página 19 de 26

1. Lower all implements and stabilizers to the ground. 2. Stop the engine and move the control levers to all positions to release system pressure. 3. Install 6V3965 Nipple and 3J1907 Seal to system pressure port (1) and signal pressure port (3). 4. Connect 6V3965 Differential Pressure Gauge to system pressure tap (1) and to signal pressure tap (3). 5. Start the engine and run at low idle rpm. Check for leaks. 6. Warm up the hydraulic oil. Check for leaks. 7. Bring the engine to high idle rpm. 8. Raise the boom control lever to a position between HOLD and FULL RAISE positions. Read the gauge. This is the margin pressure or the difference between pump discharge and signal pressure from the pump. the margin pressure should be 2100 ± 100 kPa (305 ± 15 psi). 9. If margin pressure is not correct, see Compensator Valve Adjustments in this section. NOTE: After performing compensator valve adjustments, recheck the margin pressure.

Compensator Valve Adjustments NOTICE When the compensator is rebuilt, be sure pressure compensator adjustment is backed out to a low pressure setting before engine is started. Severe pump and system damage could be the result.

Pump compensator valve (2) can be tested by running one of the pump discharge tests. The high pressure stall test will tell if the pressure spool in compensator valve (2) needs adjusted. The margin pressure test and low pressure standby test will tell if the flow spool in compensator valve (2) needs adjusted.

Compensator Valve (4) Adjusting screw. (5) Locknut. (6) Adjusting screw. (7) Lock nut.

05/04/2013


Página 20 de 26

Pressure Compensator Spool Adjustment Adjustments to the pressure compensation spool can be made on the machine. If the high pressure stall test indicates an adjustment is needed, follow this procedure: 1. Lower all implements and stabilizers to the ground. 2. Stop the engine and move the control levers to all positions to release system pressure. 3. Remove adjusting screw (6) cap. Loosen locknut (7) and turn the adjusting screw (6) clockwise to increase the pressure setting and counterclockwise to decrease the setting. NOTE: One turn equals 725 kPa (105 psi). 4. Repeat the high pressure stall test to make sure the pressure setting is 20 700 ± 350 kPa (3000 ± 50 psi). 5. When the pressure is adjusted correctly, stop the engine. Tighten locknut (7) and replace cap.

Flow Compensator Spool Adjustment Adjustments to the flow compensator spool can be made on the machine. If the margin pressure or low pressure standby test indicates an adjustment is needed, follow this procedure: 1. Lower all implements and stabilizers to the ground. 2. Run the engine at high idle. 3. Remove adjusting screw (4) cap. Loosen locknut (5) and turn adjusting screw (4) clockwise to increase the pressure setting and counterclockwise to decrease the setting. 4. Adjust low pressure standby to 2200 ± 70 kPa (320 ± 10 psi). 5. Repeat the margin pressure test to make sure the pressure setting is 2100 ± 100 kPa (305 ± 15 psi). 6. When the pressure is adjusted correctly, stop the engine. Tighten locknut (7) and replace cap.

Relief Valves Make reference to WARNING on first page of Testing And Adjusting section. There is no main line relief valve. The pressure spool of the compensator valve acts as a main line relief. It limits system pressure to 20 700 kPa (3000 psi). This can be checked on the machine without supplemental pump pressure. The boom, head end relief valve, is the only other implement relief that can be checked on the machine without supplemental pump pressure. All other implement relief valves are set above the pump compensator spool setting. These all require supplemental pump pressure to check.

05/04/2013


Página 21 de 26

Loader Control Valve Group (14) Lift rod end. (15) Tilt rod end. (16) Multi-purpose bucket rod end. (17) Tilt head end.

Bench Test

05/04/2013


Página 22 de 26

1. Lower all implements and stabilizers to the ground. 2. Stop the engine and move all the control levers to all positions. This releases system pressure. 3. Relieve hydraulic tank pressure. 4. Remove the relief valve to be tested. 5. Install the relief valve in the 1U5216 Manifold. 6. Connect the manifold to the hydraulic test bench. 7. Slowly increase pressure. Note the pressure the relief valve opens. Make an adjustment if needed.

On Machine Tests The boom, head end relief valve can be checked on the machine without supplemental pump pressure. Use the procedure that follows: 1. Lower all implements and stabilizer to the ground. 2. Stop the engine and move all the control levers to all positions. This releases system pressure. 3. Relieve tank pressure. 4. Install a 0 to 28 000 kPa (0 to 4000 psi) gauge in signal line pressure tap (1). 5. Start the engine and run at high idle rpm. 6. Warm up the oil. 7. Move the boom to the transport position and lock it in place. 8. Run the engine at low idle. 9. Move the control lever to the DOWN position to initiate a stall. 10. See the chart for correct pressure settings and tolerances. All other relief valve tests require a supplemental pump supply.

05/04/2013


Página 23 de 26

05/04/2013


Página 24 de 26

Backhoe Control Valve Group (18) Boom head end relief valve. (19) Right swing rod end relief. (20) Bucket head end relief. (21) Stick rod end relief valve. (22) Boom rod end relief valve. (23) Left swing rod end relief. (24) Bucket rod end relief valve. (25) Stick head end relief valve.

Use the following procedure to check all implement relief valves except the boom head end. The testing location will change for each relief valve circuit. There are two possible fitting sizes used depending on the circuit being tested.

Adapter Assemblies (26) 1P2375 Quick Disconnect (male). (27) 5B1309 Coupling. (28) 8T4238 Adapter. (29) 6V8632 1"-14 thd Connector. (30) 6V8639 13/16"-16 thd Connector. (31) 1P2376 Quick Disconnect [female (not shown)].

1. Assemble two adapter assemblies similar to the picture. 2. Lower all implements and stabilizers to the ground. 3. Stop the engine and move all control levers to all positions. This releases system pressure. 4. Relieve tank pressure. 5. Break the circuit being tested at the cylinder connection. For example, if the boom head end relief valve is being checked, disconnect the line or tube where it connects to the head end of the cylinder. Some oil may

05/04/2013


Página 25 de 26

drain from the line when disconnected. 6. Install the right adapter assembly into the hose or tube that goes back to the control valve. Make sure the right O-ring is installed correctly. Do not install adapter into the cylinder. 7. The female end of quick disconnect (31) should be connected to 3S6224 Pump Hose. 8. Connect quick disconnect (31) to quick disconnect (26). This now completes the circuit from the supplemental pump to the control valve.

When the supplemental pump is turned on and the control valve or spool is worn or the control valve malfunctions, the implement whose circuit is being tested may move. Sudden movement of an implement can cause injury to persons on or near the machine. 9. Turn 3S6224 Pump on. Check for leaks at the connection. 10. Slowly increase pressure. Note the pressure the relief valve opens at. Check this actual pressure to the chart.

NOTICE Pump 3S6224 only has a two gallon reservoir. Pump damage may result if run with an empty reservoir.

Adjustments

Make reference to the WARNING On the first page of Test And Adjusting section. See the subject Relief Valves when testing relief valves.

Typical Makeup And Relief Valve (32) Cap. (33) Locknut. (34) Adjusting screw.

1. Remove protective cap (32). 2. Loosen locknut (33)

05/04/2013


Página 26 de 26

3. Turn adjusting screw (34) clockwise for an increase. Turn adjusting screw (34) counterclockwise for a decrease in the pressure setting of the relief valve. 4. After screw (34) is turned for an adjustment, tighten locknut (33) and re-test the adjustment. 5. Install cap (32) after the adjustments are correct.

Copyright 1993 - 2013 Caterpillar Inc. All Rights Reserved. Private Network For SIS Licensees.

Fri Apr 5 09:33:18 CST 2013

05/04/2013

416B Hyd Test & Adjusting

Recommend Documents