Troubleshooting
PROBLEM 1: System does not vibrate.
PROBABLE CAUSE:
This problem may be caused by mechanical failure, such as a break in the control linkage or damaged components in the drum. Otherwise, the problem may be in the hydraulics. The pump or motor may have failed, or there could be a lack of hydraulic oil in the tank.
1. Check control cable linkage from vibratory control lever to pump. Make sure connections are secure and control lever operates smoothly.
2. Check the level of oil in the hydraulic tank. Add oil if it is low. Check the lines, hoses, connections, and components for leaks.
3. Check for damage to vibratory motor.
4. Check for damage to vibratory pump. Check operation of check/relief valves in pump.
5. Check splined coupling and drive shaft inside drum. If broken, vibratory motor can rotate without turning the eccentric weight shaft.
6. Check weight bearings inside drum. If bearings are damaged, they can prevent the eccentric weight shaft from turning.
PROBLEM 2: System does not reach full vpm.
PROBABLE CAUSE:
Low vpm's may be caused by a problem with the weight bearings, or by worn or damaged components reducing oil flow through the system.
1. Check the level of oil in the hydraulic tank. If the level of the oil is below the return line, air can get into the oil.
2. Check operation of vibratory control lever and control cable linkage. See if pump control handle is stopped short of full travel.
3. Check vibratory motor for excessive wear.
4. Check vibratory pump for damage or excessive wear.
5. Check operation of check/relief valves in pump.
6. Check shuttle valve and relief valve cartridges in cooling and test manifold.
7. Check weight bearings inside drum for binding.
PROBLEM 3: The oil in the system gets too hot.
PROBABLE CAUSE:
The common causes of heat in a hydraulic system are: low oil level in the tank, a pressure setting on a relief valve that is too low, a restriction in a line that causes an orifice effect, or excessive mechanical friction.
1. Check the level of oil in the hydraulic tank. Add oil if it is low. Check the lines, hoses, connections, and components for leaks.
2. Check the operation of the check/relief valves in the vibratory pump. If either one is stuck open or malfunctioning, high oil temperature will result.
3. Check the system for a restriction in an oil line. A restriction in the pump supply line will reduce the flow of oil to the pump and cause the pump to become very hot. A restriction in a line that is between the pump and the implements will cause a reduction in efficiency and high oil temperature. Removal of the restriction will normally solve the problem.
4. Check the operation of the shuttle valve and relief valve in the cooling and test manifold. If these valves do not operate properly, the flow of hot oil to the hydraulic tank may be restricted.
5. Check vibratory pump charge pressure. Loss of charge pressure can cause excessive heat build-up in the system.
PROBLEM 4: Excessive noise or vibration.
PROBABLE CAUSE:
The probable cause of excessive noise from the pump is air in the system. The noise is caused by aeration (air bubbles at the inlet side). Excessive noise may also be caused by a low setting on a relief valve, improperly installed plumbing, or rough weight bearings.
1. Check the level of oil in the hydraulic tank. If the level of the oil is below the return line, air can leak in when the pump is working.
2. Check the hose and connections between the tank and the pump for leaks. If oil can leak out when the machine is sitting idle, air can leak in when the pump is working.
3. Another cause of air in the oil is low oil viscosity. Refer to the Operation and Maintenance Guide to make sure the correct oil is used.
4. In cold weather, the oil may be too thick to flow to the pump. Run engine until hydraulic system is warmed up and noise disappears.
5. Check relief valve settings.
6. Check hydraulic plumbing. Make sure hoses or fittings are not touching any metal that can act as a sounding board. Make sure components are bolted securely.
7. Check weight bearings inside drum for excessive wear or damage.
PROBLEM 5: Oil delivery by the pump is not according to specifications.
PROBABLE CAUSE:
Reduced pump output may be caused by a restriction in the supply line to the pump, or a low oil level in the tank. If the viscosity of the oil is too high, there will be a decrease in the flow of oil from the pump. A badly worn pump or one that has not been correctly assembled will also cause reduced output flow.
1. Check the level of oil in the hydraulic tank. Add oil if it is low.
2. Check vibratory pump charge pressure.
3. Check the supply line to the pump for a restriction. Check the tank to be sure there is not a restriction in the supply line to the pump.
4. Check the type of oil used in the system. Refer to the Operation and Maintenance Guide.
5. Remove and inspect the pump. Check it for wear and be sure that it is assembled correctly.
PROBLEM 6: Oil pressure in the system is too low.
PROBABLE CAUSE:
This problem is normally caused by leakage in the system, the opening pressure of a relief valve that is too low, or a damaged pump.
1. Carefully check the system for leakage. Remember that leakage inside a control valve cannot be easily seen.
2. Check the vibratory motor for excessive wear or damage.
3. Check the operation of the check/relief valves in the vibratory pump.
4. Check the operation of the shuttle valve and relief valve in the cooling and test manifold.
5. Remove and inspect the pump for damage and correct assembly.
6. Check splined coupling and drive shaft inside drum for broke parts.
PROBLEM 7: Oil pressure in the system is too high.
PROBABLE CAUSE:
Excessive oil pressure in the system can be caused by high mechanical friction in one of the components. The eccentric weight shaft may not be turning freely, or there may be internal damage to the vibratory motor.
1. Check level of lubricant in vibratory bearing lube reservoir. If the reservoir is over-filled, it could raise the pressure needed to drive the eccentric weight shaft.
2. Check weight bearings inside drum for binding.
3. Check for damage to vibratory motor.
PROBLEM 8: System vibrates with control lever OFF.
PROBABLE CAUSE:
This problem could be caused by a break in the control linkage or internal damage to the vibratory pump.
1. Check control cable linkage from vibratory control lever to pump. Make sure connections are secure and control lever operates smoothly.
2. Remove and inspect the pump for damage and correct assembly.
Testing and Adjusting
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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. |
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1. Move the machine to a smooth horizontal location. Move away from working machines and personnel and lower implements 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. Activate 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, 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.
During a diagnosis of the hydraulic system, remember that correct oil flow and pressure are necessary for correct operation. The output of the pump (oil flow) increases with an increase in engine speed (rpm) and decreases when engine speed (rpm) is decreased. Oil pressure is caused by resistance to the flow of oil.
When troubleshooting a possible problem in the vibratory system, perform the Visual Checks first. Then do the VPM Check. If the VPM Check indicates a problem, or if there is a different problem in the system, perform the other tests and adjustments as necessary to identify and solve the problem.
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Some of the following tests and adjustments require the vibratory system to be operated while the machine is standing still. These tests should be performed on soft material such as soft dirt or sand. If the machine cannot be run on soft soil, put several old tires under the drum before vibrating. |
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Some of the following tests and adjustments are performed with the machine engine operating. When these tests are done away from the operator's station, two people must be working. One person performs the tests and adjustments, and the other should be at the controls. This will help prevent accidental movement of machine. |
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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. |
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Visual Checks
A visual inspection of the hydraulic system and its components is the first step when a diagnosis of a problem is made. Stop the engine, lower the blade to the ground. To remove the tank filler cap, slowly turn the filler cap until it is loose. If oil comes out the bleed hole, let the tank pressure lower before the filler cap is removed. Make the following inspections:
1. Measure the oil level.
2. Look for air in the oil that is in the tank. Do this immediately after the machine is stopped. Use a clear bottle or container to get a sample of the oil. Look for air bubbles in the oil that is in the bottle.
3. Remove the filter elements and look for particles removed from the oil by the filter element. A magnet will separate ferrous particles from nonferrous particles (piston rings, o-ring seals, etc.).
4. Inspect all oil lines and connections for damage or leaks.
5. Inspect control linkage for bent, broken or damaged components.
VPM Test
Perform the following test to check the operating vpm's of the machine in high- and low-amplitude, and to check the accuracy of the vpm meter on operator's console.
1. Start the engine, following proper operating procedures. Run engine at full throttle.
2. Place vibratory system in high-amplitude by swiftly moving the vibratory control lever all the way forward.
3. Read the system vpm on the vpm meter on operator's console. The meter should read approximately 1800 vpm.
4. Hold a reed tachometer of known accuracy in one hand. Take a vpm reading of the drum at the yoke, near the drum. Isolate the tachometer with a finger as shown. The reed tachometer reading should agree with the vpm meter reading.
5. Move the vibratory control lever to STOP, then swiftly back to the low-amplitude position.
6. Repeat steps 3 and 4 to find the system vpm in low-amplitude operation.
7. Shut engine OFF.
8. If the vpm meter on console does not agree with reed tachometer, the vpm measurement system needs to be adjusted.
9. If the vpm's in high- or low-amplitude is less than 1800 vpm, there is a problem in the vibratory system. Refer to Troubleshooting, and the following tests and adjustments to identify and solve the problem.
VPM Measurement Tests
If the vpm meter does not accurately indicate system vpm, check the following procedures to determine the cause, and repair.
Pulse Pick-Up Test
Magnetic Sensor
(1) Terminals. (2) Wires. (3) Case.
1. Disconnect two electrical wires (2) from magnetic sensor.
2. Set a voltmeter on lowest ac setting. Attach voltmeter leads to magnetic sensor terminals (1).
3. Start engine and run at full throttle.
4. Move vibratory control lever fully back in the low-amplitude position.
5. There should be a reading on the voltmeter as the magnetic sensor picks up pulses from the sprocket as the drive shaft rotates.
6. If no reading is obtained, the magnetic sensor may be out of adjustment, or may need to be replaced.
7. Shut engine OFF.
Magnetic Sensor Test
Magnetic Sensor
(1) Terminals. (2) Wires. (3) Case
1. Disconnect two electrical wires (2) from magnetic sensor.
2. Touch the leads of an ohmmeter to terminals (1). Resistance should be 265 ± 30 ohms. If not, replace the magnetic sensor.
3. Set the ohmmeter on its highest setting.
4. Attach one ohmmeter lead to one of the magnetic sensor terminals (1). Touch the other ohmmeter lead to the magnetic sensor case (3).
5. Electrical resistance should be infinite. If the ohmmeter gives any reading, the magnetic sensor should be replaced.
6. Repeat steps 4 and 5 for the other terminal (1) of the magnetic sensor.
Magnetic Sensor Adjustment
Magnetic Sensor Installation
(1) Sprocket. (2) Magnetic sensor. (3) Locknut. (4) Drive shaft.
Reference: For complete information on removing items listed in step 1, see Remove Drum Support (Vibratory Side) in Vibratory Drum Disassembly and Assembly module, Form No. KEBR2361.
1. Remove vibratory motor, drum support cover, and splined coupling from vibratory end of drum.
2. Check the sprocket (1). It must be positioned directly under the magnetic sensor (2), and must be securely attached to the drive shaft (4).
3. Using a feeler gauge, check the gap between magnetic sensor and tip of sprocket tooth. Gap should be 1.57 mm (.062 in.).
4. Adjust gap, if necessary, by loosening locknut (3) and turning magnetic sensor in or out until correct gap is obtained.
5. Retighten locknut (3).
Reference: For complete information on installing items listed in step 6, see Install Drum Support (Vibratory Side) in Vibratory Drum Disassembly and Assembly module, Form No. KEBR2361.
6. Install splined coupling, drum support cover, and vibratory motor to vibratory end of drum.
VPM Meter Calibration
If the vpm meter functions but is not accurate, calibrate the meter as follows.
VPM Meter
(1) VPM meter. (2) Calibration screw.
1. Start engine and run at full throttle.
2. Move the vibratory control lever fully back in the low-amplitude position.
3. Hold a reed tachometer of known accuracy in one hand. Take a vpm reading of the drum at the yoke, near the drum. Isolate the tachometer from the frame with a finger as shown.
4. Use an allen wrench to adjust the calibration screw (2) on the back of the vpm meter (1), so the meter agrees with the reed tachometer.
5. Shut engine OFF.
NOTE: If the previous VPM Measurement Tests check out all right but the vpm meter still does not work, the vpm meter may be broken, or the wiring to the meter may be faulty.
Vibratory Control Linkage Check
Check the control linkage if the vibratory system does not work, if vpm's are too low, or if system vibrates when vibratory control lever is OFF.
Pump Control Linkage
(1) Clevis. (2) Control handle. (3) Vibratory pump. (4) Control linkage. (5) Locknut.
1. Check control linkage (4) from vibratory control lever to pump. Make sure connections are secure and that vibratory control lever operates smoothly.
2. Disconnect clevis (1) at vibratory pump control handle (2).
3. Start engine and run at full throttle.
4. Manually move control handle (2) fully forward or backward to operate the vibratory system in high- or low-amplitude. Observe system vpm's.
5. Shut engine OFF.
6. If the system vibrates at 1800 vpm when manually operating the control handle, but not when moving the vibratory control lever, check the control linkage for a problem.
7. If manually moving the control handle does not provide 1800 vpm, refer to Troubleshooting and the following Tests and Adjustments to identify and solve the problem.
8. Set the vibratory control lever in the STOP position. Springs in the pump should hold control handle (2) in the center/stop position.
9. Control linkage (4) must line up with control handle (2) so clevis (1) can be installed without moving vibratory control lever or control handle.
10. If control linkage does not line up with control handle, loosen locknut (5). Turn clevis (2) in or out as necessary, to line parts up. Tighten locknut (5).
11. Install clevis (1) to vibratory pump control handle (2).
NOTE: After completing this procedure, check to make sure the vibratory control lever and the pump control handle are both in the center position.
System Pressure Test
Perform the following procedure to measure the system hydraulic pressure when vibrating in high- or low-amplitude. The system hydraulic pressures listed in the following steps assume the drum has been run up on a pile of old tires. Normal hydraulic pressure will be higher if the drum is vibrated on soft earth or gravel, as indicated on the following table.
Test Port Locations
(1) Test port X1. (2) Test port X2.
1. Remove cap from test port X1 (1) behind operator's seat. Install a 0 to 28 000 kPa (0 to 4000 psi) pressure gauge.
2. Start engine and run at full throttle.
3. Move the vibratory control lever fully forward in the high-amplitude position. Observe the pressure gauge.
4. Hydraulic pressure should peak at about 17 200 kPa (2500 psi), then decrease to about 6550 kPa (950 psi) as the vibratory motor gets up to speed.
5. Shut engine OFF. Make sure all hydraulic pressure is removed from the system. Remove pressure gauge from test port X1 and replace cap.
6. Remove cap from test port X2 (2). Install the pressure gauge.
7. Start engine and run at full throttle.
8. Move the vibratory control lever fully back in the low-amplitude position. Observe the pressure gauge.
9. Hydraulic pressure should peak at about 17 200 kPa (2500 psi), then decrease to about 5860 kPa (850 psi) as the vibratory motor gets up to speed.
10. Shut engine OFF. Make sure all hydraulic pressure is removed from the system. Remove pressure gauge from test port X2 and replace cap.
11. If the peak pressure is too high in high- or low-amplitude, the appropriate check/relief valve in the vibratory pump may need to be replaced.
12. If the operating pressure is too low, the appropriate check/relief valve in the vibratory pump may be bad. Otherwise, the shuttle valve in the cooling and test manifold may be leaking, or the vibratory motor may be leaking across the gears excessively.
13. If the operating pressure stays 3450 kPa (500 psi) or more, above normal system pressure (refer to table), there is a problem in the system. The weight bearings in the drum may need to be replaced, or the vibratory bearing lube reservoir may be over-filled.
Pump Efficiency Test
Vibratory Pump
(1) High-amplitude pressure port. (2) Low-amplitude pressure port. (3) Hydraulic hose to cooling and test manifold. (4) Hydraulic hose to cooling and test manifold. (5) Hydraulic hose to vibratory motor. (6) Hydraulic hose to vibratory motor.
1. Go through the floor opening behind operator's seat. Identify the high-amplitude pressure port (1), and the low-amplitude pressure port (2), on the vibratory pump.
2. Disconnect two hydraulic hoses (3) and (4) leading from vibratory pump to the cooling and test manifold. Mark the two hoses for reassembly. Plug the hose ends. Cap the fittings on the pump with caps capable of withstanding 17 200 kPa (2500 psi).
3. Disconnect two hydraulic hoses (5) and (6) leading from vibratory pump to the vibratory motor. Mark the two hoses for reassembly. Plug the hose ends.
4. Install inlet line of a flow meter to high-amplitude pressure port (1). Install outlet line of flow meter to low-amplitude pressure port (2).
5. Open the manual load valve (on flow meter) fully.
6. Start engine and run at full throttle.
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Avoid damage to flow meter. Do not move vibratory control lever to low-amplitude position. Read instructions for flow meter before use. |
7. Move the vibratory control lever fully forward in the high-amplitude position.
8. Slowly close the manual load valve (on flow meter) to set system pressure at 8960 kPa (1300 psi).
9. Observe flow meter. Record pump output reading.
10. Shut engine OFF. Ensure all hydraulic pressure is removed from the system. Disconnect flow meter.
11. Install inlet line of flow meter to low-amplitude pressure port (2). Install outlet line of flow meter to high-amplitude pressure port (1).
12. Open the manual load valve (on flow meter) fully.
13. Start engine and run at full throttle.
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Avoid damage to flow meter. Do not move vibratory control lever to high-amplitude position. Read instructions for flow meter before use. |
14. Move the vibratory control lever fully back in the low-amplitude position.
15. Slowly close the manual load valve (on flow meter) to set system pressure at 8960 kPa (1300 psi).
16. Observe flow meter. Record pump output reading.
17. Shut engine OFF. Ensure all hydraulic pressure is removed from the system. Disconnect flow meter.
18. Reinstall hydraulic hoses (3), (4), (5), and (6) to the vibratory pump.
19. Pump output should be approximately 114 liter/min (30 U.S. gpm) in both high- and low-amplitude.
20. If pump output is less than 95 liter/min (25 U.S. gpm) in either high- or low-amplitude, refer to Troubleshooting for probable cause and remedy.
Charge Pressure Test
Vibratory Pump
(1) Charge oil inlet port. (2) High-amplitude pressure port. (3) Low-amplitude pressure port. (4) Hydraulic hose to vibratory motor. (5) Hydraulic hose to vibratory motor.
1. Go through the floor opening behind operator's seat. Identify the charge oil inlet port (1), the high-amplitude pressure port (2), and the low-amplitude pressure port (3), on the vibratory pump.
2. Install a tee and a 0 to 4100 kPa (0 to 600 psi) pressure gauge in the hydraulic hose leading to the charge oil inlet port (1).
3. Disconnect two hydraulic hoses (4) and (5) leading from the pump to the vibratory motor. Mark the two hoses for reassembly. Plug the hose ends.
4. Install inlet line of a flow meter to high-amplitude pressure port (2). Install outlet line of flow meter to low-amplitude pressure port (3).
5. Open the manual load valve (on flow meter) fully.
6. Start engine and run at full throttle.
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Avoid damage to flow meter. Do not move vibratory control lever to low-amplitude position. Read instructions for flow meter before use. |
7. Move the vibratory control lever fully forward in the high-amplitude position.
8. Slowly close the manual load valve (on flow meter) to set system pressure at 13 790 kPa (2000 psi).
9. Observe pressure gauge. Record charge pressure reading.
10. Shut engine OFF. Ensure all hydraulic pressure is removed from the system. Disconnect flow meter.
11. Remove the tee and pressure gauge from the hydraulic hose leading to the charge oil inlet port (1).
12. Reinstall hydraulic hoses (4) and (5) to vibratory pump.
13. Charge pressure should be approximately 1655 to 2140 kPa (250 to 310 psi).
14. If charge pressure is less than 1380 kPa (200 psi), the charge relief valve in the pump may be damaged. Otherwise there may be excessive leakage in the pump, or the charge pump may be damaged or not getting enough oil.
Motor Case Drain Test
Vibratory Motor
(1) Case drain port. (2) Case drain line. (3) High-amplitude pressure line. (4) Low-amplitude pressure line.
1. Disconnect the case drain line (2) from the vibratory motor.
2. Install inlet line of a flow meter to the case drain port (1) of vibrator motor. Install outlet line of flow meter to the case drain line (2).
3. Open manual load valve (on flow meter) fully.
4. Start engine and run at full throttle.
5. Move the vibratory control lever fully back in the low-amplitude position.
6. Observe flow meter. Case drain flow should be less than 3.8 liters/min (1.0 U.S. gpm).
7. Repeat steps 5 and 6 for the high-amplitude position.
8. Shut engine OFF.
9. If case drain flow is unusually high, repair or replace the vibratory motor.
Cooling and Test Manifold Flow Test
Cooling and Test Manifold
(1) Port T. (2) Hydraulic return line.
1. Disconnect the hydraulic return line (2) from port T (1) of cooling and test manifold. The manifold is located in engine compartment, behind operator's seat.
2. Install inlet line of a flow meter to port T (1). Install outlet line of flow meter to hydraulic return line (2).
3. Open manual load valve (on flow meter) fully.
4. Start engine and run at full throttle.
5. Observe and record the flow meter reading with vibratory control lever in the STOP position.
6. Move vibratory control lever fully forward in the high-amplitude position.
7. Observe and record the flow meter reading.
8. Move vibratory control lever to STOP, then fully back in the low-amplitude position.
9. Observe and record the flow meter reading.
10. Shut engine OFF.
11. Flow meter should read zero when vibratory control lever is OFF. Flow meter should read approximately 19 liter/min (5 U.S. gpm) in both high- and low-amplitude.
12. If return line flow is too high or too low, check the operation of the shuttle valves and relief valves in the cooling and test manifold. If this does not solve the problem, check the pressure settings of the two relief valves in the manifold.
Relief Valve and Shuttle Valve Check
The cooling and test manifold contains two identical relief valves and two identical shuttle valves. One set is for the vibratory system, and one set is for the propel system. When checking the operation of these valves, all the valves should be removed and checked using the following procedure.
Cooling and Test Manifold
(1) Propel relief valve. (2) Propel shuttle valve. (3) Vibratory relief valve. (4) Vibratory shuttle valve.
1. Remove the relief valve cartridges (1) and (3), and the shuttle valve cartridges (2) and (4), from the cooling and test manifold.
2. Inspect the cartridges for visible contamination. Flush with clean mineral spirits to remove contaminants.
3. After flushing, blow dry with clean filtered air.
4. Through the nose of the cartridge, manually operate the inner working parts several times. Use a wooden or plastic dowel to avoid damaging seals or finished surfaces of the valve.
5. If the inner working parts do not operate properly, dispose of the cartridge and replace with a new one.
6. Inspect the cartridge seals for damage. Replace if necessary.
7. Install the valve cartridges into the manifold. Tighten the cartridges to 40 to 47 N-m (30 to 35 lb. ft.).
Relief Valve Pressure Test
There are two identical relief valves in the cooling and test manifold. One is for the vibratory system, and one is for the propel system. When checking the pressure setting of a relief valve, both relief valve cartridges should be removed and tested.
Relief Valve Cartridge
(1) Adjusting screw. (2) Locknut
1. Remove one relief valve cartridge from the manifold. Install the relief valve cartridge in a hydraulic test circuit.
2. Start the test circuit. Read the pressure setting of the relief valve on the pressure gauge.
3. The pressure gauge should read 1650 kPa (240 psi) with a 19 liter/min (5 U.S. gpm) flow.
4. Shut test circuit off.
5. If pressure setting is too high or too low, loosen locknut (2) while holding the adjusting screw (1) to prevent it from turning.
6. Turn adjusting screw in (clockwise) to increase pressure setting, or out (counterclockwise) to decrease pressure setting. 1 turn = approximately 241 kPa (35 psi).
7. When operating pressure is correct, tighten locknut (2) while holding adjusting screw (1) to prevent it from turning.
8. If turning the adjusting screw does not change the pressure setting, the relief valve should be discarded and replaced with a new part.
9. Install the relief valve cartridge in the manifold. Tighten the cartridge to 40 to 47 N-m (30 to 35 lb. ft.).
10. Repeat steps 1 through 9 for the other relief valve cartridge.