Introduction

Reference: For Specifications with illustrations, refer to the Specifications for the CB-534 Vibration System, Form No. KENR2424. If the Specifications in Form No. KENR2424 are not the same as listed in the Systems Operation and the Testing And Adjusting, look at the print date on the back cover of each book. Use the Specifications listed in the book with the latest date.

Troubleshooting

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.

The 6V4161 Pressure Gauge Kit can be used to make pressure tests on the vibration system. Before any tests are made, visually inspect the complete hydraulic system for leakage of oil and for parts that are damaged. For some of the tests a magnet and a mm (in) measuring rule are usable tools

NOTE: The 6V4161 Pressure Gauge Kit has JIC connectors and NPT threads on the fittings. JIC-to-metric and NPT-to-metric adapters must be used as necessary when checking pressures on this machine.

When any test is made of the vibration system, the hydraulic oil must be at the normal temperature for operation.

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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 vibration system.

1. Move the machine to a smooth horizontal location. Move away from working machines and personnel.

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 lever to all positions to release any pressure in the hydraulic system.

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

7. Make sure all hydraulic pressure is released before any fitting, hose or component is loosened, tightened, removed or adjusted.

Visual Checks

A visual inspection of the vibration system and its components is the first step when a diagnosis of a problem is made. Then check the operation of the machine. Finally, check the vibration system with instruments. Stop the engine, make the following inspections.

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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.

1. Check the oil level of the hydraulic tank.

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. Check the oil level in the pump splitter box drive.

4. Check all oil lines, hoses and connections for leaks and damage. Look for oil on the ground under the machine.

5. Remove and check the hydraulic filter element for foreign materials.

a. Bronze-colored particles give an indication of pump portplate failure.

b. Shiny steel particles give an indication of pump or motor piston failure or motor cam deterioration.

c. Rubber particles give an indication of a seal or hose failure.

d. Aluminum particles give an indication of steering pump failure.

Whenever foreign particles such as rubber or metal are found, all the components of the propulsion, vibration and steering circuits must be flushed through. Each loop line circuit must be independently filtered. Do not use parts that have been damaged.

6. Inspect control linkage for bent, broken or damaged components.

Checks During Operation

With the engine running, operate the machine in each direction and in both speed ranges. Make note of all noises that are not normal and find their sources. If the operation is not correct, refer to the list of problems and probable causes.

The checks during operation can be used to find leakage in the system. They can also be used to find a bad valve, pump or motor. Vibratory frequency can be used to check the condition of the vibration motors and the pump.

Prior to checking the vibration system, drive the machine backwards and forwards several times operating the propulsion controls in all speed ranges. While the machine is being driven backwards and forwards, check the condition of the rubber blocks. The blocks act as an isolator between vibrating and non-vibrating parts of the machine.

Dual Drum Vibration Mode

1. Ensure that the amplitude settings for both drums are identical.

2. Watch both drums. Starting and stopping operations should be progressive. Drum rotation should be smooth and regular at all times. The vibration system should start up only when the propulsion control lever is moved forward or backward.

3. Check that both drums vibrate.

4. After selecting the vibratory frequency of the compactor, the frequency values should be identical for forward and reverse travel motion.

5. Check that the vibratory mechanism in each drum is rotating in the same direction as the drums. Direction of rotation can be seen on the amplitude selector mounted on each drum.

6. Check that both vibratory systems stop as soon as the propulsion control lever is moved to neutral.

7. Check that the vibratory mechanism in each drum reverses its direction of rotation when the compactor is reversed.

8. Check for noise from the pump and drive motors.

9. Check for the sound of the relief valves opening. The opening pressures of the relief valves are given in Relief Valve Pressure Tests in Testing And Adjusting.

Single Drum Vibration Mode

1. Watch the drum which has been chosen to vibrate. Starting and stopping operations should be progressive. Drum rotation should be smooth and regular at all times. When the propulsion control lever is moved forward or backward, the vibration system should start up on the selected drum only.

2. After selecting the vibratory frequency of the compactor, the frequency values should be identical for forward and reverse travel motion.

3. Check that the vibratory mechanism in the drum that is vibrating is rotating in the same direction as the drums. Direction of rotation can be seen the on amplitude selector mounted on drum.

4. Check that the vibratory system switches off as soon as the propulsion control lever is moved to neutral.

5. Check that the vibratory mechanism reverses its direction when the direction of the compactor is reversed.

6. Check for noise from the pump and drive motors.

7. Check for the sound of the relief valves opening. The opening pressures of the relief valves are given in Relief Valve Pressure Tests in Testing And Adjusting.

Problem: Vibration does not work in forward or reverse travel.

Probable Cause:

1. Low oil pressure caused by:

a. Low oil level in hydraulic tank.

b. Restricted hydraulic filter element.

c. Failure of the charge pump.

d. Charge pump relief valve adjustment not correct.

e. Failure of the regulator block.

f. Failure of the direction control valve.

g. Main relief valve adjustment is not correct or valve does not close.

h. Pump portplate wear causing excessive leakage from the high pressure line to the pump housing.

j. Motor portplate wear.

2. Failure of the drive coupling.

3. Failure in the splitter box drive.

4. Faulty vibration on/off contactor on the dashboard.

5. Faulty vibration mode valve group.

6. Faulty vibration mode valve selector switch on the dashboard.

7. Mechanical failure of the vibrator mechanism.

Problem: Vibration does not work in forward travel, while in single or dual drum mode.

Probable Cause:

1. Main relief valve for vibration in forward travel is incorrectly adjusted or is damaged.

2. Failure of the hydraulic regulator.

3. Faulty solenoid on the direction control valve.

4. Failure of the rocker arm section of the pump swashplate assembly.

5. Fault in the electric circuit wiring.

6. Faulty electric contactor mounted on the propulsion control lever. (Earlier machines)

7. Faulty vibration control relay located in the console support.

8. Faulty pressure switch at propel pump. (Later machines)

Problem: Vibration does not work in reverse travel, while in single or dual drum mode.

Probable Cause:

1. Main relief valve for vibration in reverse travel is incorrectly adjusted or is damaged.

2. Failure of the hydraulic regulator.

3. Faulty solenoid on the direction control valve.

4. Failure of the rocker arm section of the pump swashplate assembly.

5. Fault in the electric circuit wiring.

6. Faulty electric contactor mounted on the propulsion control lever. (Earlier machines)

7. Faulty vibration control relay located in the console support.

8. Faulty pressure switch at propel pump. (Later machines)

Problem: Periodic loss of vibration in forward or reverse, while in single or dual drum mode.

Probable Cause:

1. Faulty vibration on/off contactor.

2. Cover plate used to operate on/off contactor is not secured correctly. (Earlier machines)

3. Loose connection in the electric circuit wiring.

Problem: Slow vibration frequency start-up. Excessive time lag after travel starts.

Probable Cause:

1. Flow restriction orifice in the pilot line to the hydraulic regulator is partially blocked.

Problem: Harsh engagement of vibration.

Probable Cause:

1. Charge circuit relief valve is not correctly adjusted. It is set too high.

Problem: Slow vibration frequency stopping. Travel stops before vibration.

Probable Cause:

1. Flow restriction orifice in the pilot line to the hydraulic regulator is partially blocked.

Problem: Vibration does not stop when propulsion lever is brought back to neutral.

Probable Cause:

1. Faulty hydraulic regulator or incorrect neutral adjustment.

2. Faulty spool assembly in the direction control valve.

3. Faulty vibration control relay.

4. Faulty electric contactor mounted on the propulsion control lever. (Earlier machines)

5. Faulty pressure switch at propel pump. (Later machines)

Problem: Compactor will not reach maximum vibration frequency.

Probable Cause:

1. Engine high idle is not correctly adjusted.

2. Frequency gauge is defective or not correctly adjusted.

3. Failure of the charge pump.

4. Charge pump relief valve adjustment is not correct.

5. Pump portplate wear causing excessive leakage from the high pressure line to the pump housing.

6. Motor portplate wear.

7. Adjustment of the maximum pump displacement is not correct.

Problem: Variation in maximum frequency readings between forward and reverse rotation.

Probable Cause:

1. Incorrect neutral adjustment of the hydraulic regulator.

2. Mechanical failure of the hydraulic regulator.

3. Main relief valve adjustment is not correct or valve does not close correctly on one side of the loop line.

4. Failure of the rocker arm section of the pump swashplate assembly.

5. Adjustment of the maximum pump displacement is not correct.

Problem: Compactor will only vibrate in dual drum vibration mode.

Probable Cause:

1. Vibration mode selector switch failure.

2. Electric circuit failure.

3. Mechanical failure of the vibration mode solenoid valve.

4. Mechanical failure of the vibration mode selector valve.

Problem: Compactor will only vibrate in single drum vibration mode. The same drum vibrates at all vibrator mode selector switch positions.

Probable Cause:

1. Vibration mode selector switch failure.

2. Mechanical failure of the vibration mode solenoid valve.

3. Mechanical failure of the vibration mode selector valve.

Problem: Noisy vibratory mechanism.

Probable Cause:

1. Lack of lubrication oil in the vibrator housing.

2. Loose retaining bolts for the vibrator drive shaft.

3. Loose retaining bolts for the vibrator motor.

4. Vibration frequency is too low.

Problem: Hydraulic circuit oil overheats.

Probable Cause:

1. Incorrect type of oil used in the hydraulic system.

2. Hydraulic cooler is restricted.

3. Excessive internal leakage in the circuit.

4. Not enough charge line pressure.

System Tests And Adjustments

Pump Efficiency Check

For any pump test at a given rpm, the pump flow at 690 kPa (100 psi) will be larger than the pump flow at 6900 kPa (1000 psi). The difference between the pump flow of the 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.

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

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^*The numbers in the examples are for illustration and are not values for any specific pump or pump condition. See Specifications for pump flow of a new pump at 690 kPa (100 psi) and 6900 kPa (1000 psi).

Machine Test

Install a Flow Meter. For Formula I, measure pump flow at 690 kPa (100 psi) and at 6900 kPa (1000 psi) with the engine at high idle rpm.

Bench Test

If the test bench can be run at 6900 kPa (1000 psi) and at full pump rpm, find the percent of flow loss using Formula I.

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

Vibratory Frequency Test

The oil in the system must be Service Classification ISO 3448 type VG 46 hydraulic oil. The oil must be certified to have anti-rust, very high viscosity index and anti-oxidation additive properties for heavy duty use. The oil temperature must be at 60 ± 3°C (140 ± 5°F) to get correct results. All frequency tests are made with the engine rpm at maximum 2230 rpm.

Tests must be carried out on a material which has been compacted to a reasonable density.

Vibratory frequencies that are shown below are an indication that the circuit operation is normal. The relief valves for both the charge pump and main line closed circuits must be tested to be sure that the opening pressure of each is correct.

NOTE: The maximum frequency values shown below are examples only. Actual values during the test may vary from those shown due to engine, hydraulic components and ground conditions. However, the difference in vibrations per minute (vpm) at each amplitude setting should be as shown.

Dual Drum Frequency Test

Forward And Reverse Travel

Vibrator position ... indicator one

Low nominal amplitude setting ... 0.36 mm (.014 in)

Maximum frequency at ... 2600 vpm

Vibrator position ... indicator two

Average nominal amplitude setting ... 0.81 mm (.032 in)

Maximum frequency at ... 2550 vpm

Vibrator position ... indicator three

High nominal amplitude setting ... 1.08 mm (.043 in)

Maximum frequency at ... 2500 vpm

Single Drum Frequency Test

Forward And Reverse Travel

Vibrator position ... indicator one

Low nominal amplitude setting ... 0.36 mm (.014 in)

Maximum frequency at ... 2660 vpm

Vibrator position ... indicator two

Average nominal amplitude setting ... 0.81 mm (.032 in)

Maximum frequency at ... 2630 vpm

Vibrator position ... indicator three

High nominal amplitude setting ... 1.08 mm (.043 in)

Maximum frequency at ... 2600 vpm

Pressure Test Tools

Use the above pressure gauge kit for all of the pressure tests that follow. In some procedures, more than one of the same pressure gauge is required. It may be necessary to use two pressure gauge kits. Also included in the above chart are any other required tools for the following pressure tests.

NOTE: The 6V4161 Pressure Gauge Kit has JIC connectors and NPT threads on the fittings. JIC-to-metric and NPT-to-metric adapters must be used as necessary when checking pressures on this machine.

Charge Pump System Pressure Test

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Refer to the WARNING on the first page of Troubleshooting.

1. Make sure that the parking brake is applied. Make sure the propulsion control lever is in neutral. Also make sure the travel speed selector is in the zero travel speed position.

Charge Pump System Pressure Test
(1) Pressure gauge. (2) Pressure tap. (3) Vibration pump.

2. Connect 4000 kPa (600 psi) pressure gauge (1) from the 6V4161 Pressure Gauge Kit to pressure tap (2) on vibration pump (3) with a 814543 Connector.

3. Start and run the engine at 1500 rpm. Look at the pressure gauge. The relief valve pressure reading should be 2000 ± 100 kPa (290 ± 15 psi).

Relief Valve Adjustment
(4) Adjustment screw. (5) Locknut.

4. If the relief valve pressure is not correct, it must be adjusted. Loosen locknut (5). Use an allen wrench to turn adjustment screw (4) clockwise to increase the pressure or counterclockwise to decrease the pressure.

5. After the relief valve pressure is adjusted correctly, tighten the locknut. Remove the pressure gauge from pressure tap (2).

Main Relief Valve Pressure Test

Forward Drive

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Refer to the WARNING on the first page of Troubleshooting.

NOTE: Do the Charge Pump System Pressure Test before doing the main relief valve test.

1. Make sure that the parking brake is applied and the propulsion control lever is in neutral. Also make sure the travel speed selector is in the zero travel speed position.

2. Place wood wedges under both sides of the two drums.

Forward Drive Main Relief Valve Pressure Test
(1) Pressure gauge. (2) Pressure gauge. (3) Hose. (4) 9S7359 Blocking Plate. (5) Pressure tap. (6) Pressure tap.

3. Connect two 60 000 kPa (9000 psi) pressure gauges (1) and (2) from the 6V4161 Pressure Gauge Kit to pressure taps (5) and (6).

4. Disconnect hose (3) from the pump. Install 9S7359 Blocking Plate (4) with an O-ring between hose (3) and the pump port.

NOTE: Steps 5. and 6. are for Earlier machines only, and Steps 7. and 8. are for Later machines only.

5. Start and run the engine at 1500 rpm. Place the vibration mode switch in the dual drum vibration position. Put the cover on the vibration on/off contactor. Release the parking brake.

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NOTICE
The return oil flow is blocked by blocking plate (4). The oil temperature will increase quickly. To prevent damage to the vibration system, do not hold the propulsion control lever in the forward position at relief valve pressure for more than three seconds.

6. Be sure that the travel speed selector is in the zero travel speed position. Move propulsion control lever fully forward. Look at pressure gauge (2). The relief valve pressure should 35 000 ± 700 kPa (5100 ± 100 psi). If the relief valve pressure is too low, look at pressure gauge (1). This is the closed circuit loop return pressure. It should be 2000 ± 100 kPa (290 ± 15 psi). If this pressure is also low, there is internal leakage in the internal circuit. See Hydraulic Motor Leakage Tests in Testing And Adjusting.

7. Start and run the engine at 1500 rpm. Place the vibration mode switch in the dual drum vibration position. Move the vibration on/off contactor to the ON position. Release the parking brake.

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NOTICE
The return oil flow is blocked by blocking plate (4). The oil temperature will increase quickly. To prevent damage to the vibration system, do not keep the jumper wire on the terminals of the pressure switch for more than three seconds.

Engine Compartment
(12) Forward pressure switch. (13) Reverse pressure switch.

8. Remove the cover from pressure switch (12). Place a jumper wire between the C and NO terminals of pressure switch (12) to start the vibration. Look at pressure gauge (2). The relief valve pressure should 35 000 ± 700 kPa (5100 ± 100 psi). If the relief valve pressure is too low, look at pressure gauge (1). This is the closed circuit loop return pressure. It should be 2000 ± 100 kPa (290 ± 15 psi). If this pressure is also low, there is internal leakage in the internal circuit. See Hydraulic Motor Leakage Tests in Testing And Adjusting.

Relief Valve Adjustment
(7) Locknut. (8) Adjustment screw.

9. If the relief valve pressure is not correct, it must be adjusted. Stop the engine. Loosen locknut (7). Use an allen wrench to turn adjustment screw (8) clockwise to increase the pressure or counterclockwise to decrease the pressure.

10. After the relief valve pressure is adjusted correctly, tighten the locknut. Remove the pressure gauges from pressure taps (5) and (6). Remove the blocking plate and reconnect hose (3).

Reverse Drive

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Refer to the WARNING on the first page of Troubleshooting.

NOTE: Do the Charge Pump System Pressure Test before doing the main relief valve test.

1. Make sure that the parking brake is applied and the propulsion control lever is in neutral. Also make sure the travel speed selector is in the zero travel speed position.

2. Place wood wedges under both sides of the two drums.

Forward Drive Main Relief Valve Pressure Test
(1) Pressure gauge. (2) Pressure gauge. (4) 9S7359 Blocking Plate. (5) Pressure tap. (6) Pressure tap. (9) Hose.

3. Connect two 60 000 kPa (9000 psi) pressure gauges (1) and (2) from the 6V4161 Pressure Gauge Kit to pressure taps (5) and (6).

4. Disconnect hose (9) from the pump. Install 9S7359 Blocking Plate (4) with an O-ring between hose (9) and the pump port.

NOTE: Steps 5. and 6. are for Earlier machines only, and Steps 7. and 8. are for Later machines only.

5. Start and run the engine at 1500 rpm. Place the vibration mode switch in the dual drum vibration position. Put the cover on the vibration on/off contactor. Release the parking brake.

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NOTICE
The return oil flow is blocked by blocking plate (4). The oil temperature will increase quickly. To prevent damage to the vibration system, do not hold the propulsion control lever in the forward position at relief valve pressure for more than three seconds.

6. Be sure that the travel speed selector is in the zero travel speed position. Move propulsion control lever fully forward. Look at pressure gauge (2). The relief valve pressure should 35 000 ± 700 kPa (5100 ± 100 psi). If the relief valve pressure is too low, look at pressure gauge (1). This is the closed circuit loop return pressure. It should be 2000 ± 100 kPa (290 ± 15 psi). If this pressure is also low, there is internal leakage in the internal circuit. See Hydraulic Motor Leakage Tests in Testing And Adjusting.

7. Start and run the engine at 1500 rpm. Place the vibration mode switch in the dual drum vibration position. Move the vibration on/off contactor to the ON position. Release the parking brake.

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NOTICE
The return oil flow is blocked by blocking plate (4). The oil temperature will increase quickly. To prevent damage to the vibration system, do not keep the jumper wire on the terminals of the pressure switch for more than three seconds.

Engine Compartment
(12) Forward pressure switch. (13) Reverse pressure switch.

8. Remove the cover from pressure switch (13). Place a jumper wire between the C and NO terminals of pressure switch (13) to start the vibration. Look at pressure gauge (2). The relief valve pressure should 35 000 ± 700 kPa (5100 ± 100 psi). If the relief valve pressure is too low, look at pressure gauge (1). This is the closed circuit loop return pressure. It should be 2000 ± 100 kPa (290 ± 15 psi). If this pressure is also low, there is internal leakage in the internal circuit. See Hydraulic Motor Leakage Tests in Testing And Adjusting.

Relief Valve Adjustment
(10) Locknut. (11) Adjustment screw.

9. If the relief valve pressure is not correct, it must be adjusted. Stop the engine. Loosen locknut (10). Use an allen wrench to turn adjustment screw (11) clockwise to increase the pressure or counterclockwise to decrease the pressure.

10. After the relief valve pressure is adjusted correctly, tighten the locknut. Remove the pressure gauges from pressure taps (5) and (6). Remove the blocking plate and reconnect hose (9).

Hydraulic Regulator Neutral Adjustment

Oil from the charge pump circuit is used to pilot the hydraulic regulator which controls the swashplate angle of the fixed displacement pump.

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Refer to the WARNING on the first page of Troubleshooting.

NOTE: Do the Charge Pump System Pressure Test before doing the hydraulic regulator neutral adjustment.

1. Make sure that the parking brake is applied. Make sure the propulsion control lever is in neutral and the travel speed selector is in the zero travel speed position.

2. Place wood wedges under both sides of the two drums.

Pressure Tap Locations
(1) Hose. (2) Port. (3) Port. (4) Pressure tap. (5) Pressure tap.

3. Connect hose (1) between ports (2) and (3). This will ensure equal oil pressure on each side of the valve piston.

4. Connect two 60 000 kPa (9000 psi) pressure gauges from the 6V4161 Pressure Gauge Kit to pressure taps (4) and (5) with two 814543 Connectors.

5. Start and run the engine at 1500 rpm.

6. Place the vibration mode switch in the dual drum vibration position.

7. Look at the pressure gauges. Both readings should be identical.

Hydraulic Regulator Neutral Adjustment
(6) Locknut. (7) Adjustment screw.

8. If it is necessary to adjust the neutral position of the piston, loosen locknut (6). Use an allen wrench to turn piston rod adjustment screw (7). Turn the screw clockwise or counterclockwise depending on the spool movement requirement. The pressures on the gauges should change. Adjust screw (7) until they are the same.

9. Stop the engine. Remove the two 60 000 kPa (9000 psi) gauges and replace them with two 4000 kPa (600 psi) gauges.

10. Repeat Steps 5 through 8.

11. Tighten locknut (6). Remove the pressure gauges, hoses and connectors from pressure taps (4) and (5). Remove the hose from ports (2) and (3).

Direction Control Valve Neutral Adjustment

Direction Control Valve
(1) Direction control valve. (2) Hydraulic regulator.

Prior to piloting hydraulic regulator (2), oil from the charge pump must pilot the spool of direction control valve (1). Do the following test to verify that the spool valve neutral setting is correct.

Do the Charge Pump System Pressure Test before doing this test. Also do the Hydraulic Regulator Neutral Adjustment before doing this test. This will ensure that the mechanical neutral position of the swashplate is correct.

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Refer to the WARNING on the first page of Troubleshooting.

1. Make sure that the parking brake is applied. Make sure the propulsion control lever is in neutral. Also make sure the travel speed selector is in the zero travel speed position.

2. Place wood wedges under both sides of the two drums.

Pressure Tap Locations
(3) Pressure tap. (4) Pressure tap.

3. Connect two 4000 kPa (600 psi) pressure gauges from the 6V4161 Pressure Gauge Kit to pressure taps (3) and (4) with 814543 Connectors.

4. Start and run the engine at 1500 rpm.

5. Place the vibration mode switch in the dual drum vibration position. Put the cover on the vibration on/off contactor.

6. Look at the pressure gauges. Both readings should be identical.

7. If the readings are not the same, the spool of the direction control valve is not in correct position. The valve must be disassembled and repaired as necessary.

8. If the readings are correct, remove the gauges and connectors from the pressure taps.

Vibration Pump Displacement Adjustment

Hydraulic Regulator
(1) Spacer. (2) Piston. (3) Adjustment screw. (4) Locknut.

When new, the pump has a displacement of 40 cm³/rev (2.44 in³/rev). Spacer (1) acts as a stop so that the stroke of piston (2) is reduced. This reduces the angle of the swashplate and therefore the maximum flow rate of the pump from 129 liter/min (34.1 U.S. gpm) to 116 liter/min (30.6 U.S. gpm).

On the opposite end of the hydraulic regulator is adjustment screw (3). This screw is used as a fine adjustment to set the piston stroke in the opposite direction to the same value that spacer (1) does.

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Refer to the WARNING on the first page of Troubleshooting.

NOTE: Do the Charge Pump System Pressure Test and Hydraulic Regulator Neutral Adjustment before this test.

1. Select a test area where the ground is in a loose condition. The area must be far enough away from buildings or structures to avoid possible damage. Never operate the vibration system with the machine on concrete.

2. Make sure that the parking brake is applied. Make sure the propulsion control lever is in neutral and the travel speed selector is in the zero travel speed position.

3. Place wood wedges under both sides of the two drums.

4. Start and run the engine at maximum rpm.

5. Place the vibration mode switch in the dual drum vibration position.

Turn on the vibration on/off switch. Release the parking brake.

NOTE: Steps 6., 7., 8., and 9. are for Earlier machines only. Steps 10., 11., 12., and 13. are for Later machines only.

6. Be sure that the travel speed selector is in the zero travel speed position. Move propulsion control lever forward until the vibration starts.

7. Look at frequency gauge and note the reading.

8. Move propulsion control lever to reverse until the vibration starts.

9. Look at frequency gauge and note the reading.

Engine Compartment
(5) Forward pressure switch. (6) Reverse pressure switch.

10. Release the parking brake. Remove the cover from pressure switches (5) and (6). Place a jumper wire between the C and NO terminals of pressure switch (5).

11. Look at the frequency gauge and note the reading.

12. Remove the jumper wire from switch (5). Place the jumper wire between the C and NO terminals of pressure switch (6).

13. Look at the frequency gauge and note the reading.

Hydraulic Regulator Adjustment
(3) Adjustment screw. (4) Locknut.

14. The forward and reverse frequency readings should be identical. If they are not, it is necessary to reset the position of adjustment screw (3). Loosen locknut (4). Turn adjustment screw (3) clockwise or counterclockwise until the forward and reverse readings are identical. Tighten the locknut.

Closed Circuit Loop Line Filtration

Loop circuit filtration must be done before the replacement of any hydrostatic circuit component. Filtration must also be done after the replacement or opening of a circuit component.

The high pressure filter unit can be positioned either in the delivery or the return line of the loop circuit. The filter position will depend on the component which is thought to be faulty or which has been replaced.

If the vibration pump has been disassembled or replaced, the filter must be installed on the delivery line from the pump. This will ensure that as soon as the pump starts to deliver oil, the oil will pass through the filter before entering the other components of the closed circuit.

If a vibration motor has been disassembled or replaced or a hose has been replaced between motor and pump, the filter must be installed on the motor return line to the pump. This will ensure that as soon as the pump starts to deliver oil, the oil will pass through the filter before entering the other components of the closed circuit.

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Refer to the WARNING on the first page of Troubleshooting.

1. Select a test area where the ground is in a loose condition. The area must be far enough away from buildings or structures to avoid possible damage. Never carry out a vibration circuit filtration test on concrete.

2. Make sure that the parking brake is applied. Make sure the propulsion control lever is in neutral and the travel speed selector is in the zero travel speed position.

Filter Unit Typical Installation
(1) Hydraulic tank. (2) Vibration mode selector valve group. (3) Loop circuit return line for forward drive. (4) Filter. (5) Front drum vibration motor. (6) Rear drum vibration motor. (7) Vibration pump. (8) High pressure loop circuit line for forward drive.

3. Select low nominal amplitude value for each vibrator.

4. Disconnect hose (3) from pump (7).

5. Install filter (4) between pump (7) and hose (3). Make sure that the arrow on the filter casing is pointing in the same direction as the flow of oil to the pump.

6. Start and run the engine at 2200 rpm.

7. Select dual drum vibration mode.

8. Turn the vibration on/off switch on.

9. Release the brakes by pulling the stop control up.

NOTE: To turn on the vibration on Earlier machines, set the travel speed selector to zero travel speed position and move the propulsion control lever forward until the vibration starts. On Later machines, remove the cover from pressure switch (9) and place a jumper wire between the C and NO terminals of forward pressure switch (9).

Engine Compartment
(9) Forward pressure switch.

10. Turn on the vibration and filter the circuit for a period of 5 minutes.

11. Reposition the vibration mode switch for front drum vibration only. Filter the circuit again for a period of 5 minutes.

12. Reposition the vibration mode switch for rear drum vibration only. Filter the circuit again for another period of 5 minutes.

13. Stop the engine. Remove the filter. Connect hose (3) to the pump again. Remove jumper wire from forward pressure switch (9).

Hydraulic Motor Leakage Tests

A certain amount of internal leakage is needed for lubrication in the hydraulic motors. Leakage above the allowed value will reduce the rotation speed of the motor and prevent the motor from developing maximum torque. All the moving components of the hydraulic motors require lubrication. The components are sealed either by the use of seals or by matching surfaces which have been machined to high precision tolerances and finish.

The two types of internal leakage found in a hydraulic motor are piston and distributor leakage. Piston leakage is when oil will pass from the supply line into the motor case, where it will be returned to the tank. Distributor leakage is when oil leakage can be from the supply line into the return line of the loop circuit. Leakage can also be from the supply line into the motor case.

Static Leakage Test Between Supply Line And Motor Case

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Refer to the WARNING on the first page of Troubleshooting.

Typical Vibration Motor Leakage Test
(1) Hydraulic tank. (2) Vibration mode selector valve group. (3) Rear drum vibration motor. (4) Vibration pump. (5) Front drum vibration motor. (6) Hose. (7) Flow meter. (8) Return line hose from rear drum vibration motor case. (9) Return line hose from front drum vibration motor case.

NOTE: The test shown is for the rear drum vibration motor. To test the front drum vibration motor, use vibration motor (5) and return line hose (9) instead of vibration motor (3) and return line hose (8).

1. Select high nominal amplitude value for vibration motor to be tested.

2. Disconnect motor case return line hose (8) from vibration motor (3). Connect hose (8) to the outlet port of flow meter (7) as shown.

3. Connect 812396 Hose (6) between the case return line port of motor (3) and the inlet port of flow meter (7) as shown.

4. Select single drum vibration mode for the drum to be tested.

5. Start and run the engine at 2230 rpm.

6. Move the travel speed selector to the zero travel speed position.

7. Release the parking brake.

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NOTICE
The maximum time for this test is 15 seconds. Exceeding the maximum time will cause the hydraulic oil temperature to increase quickly. This could cause damage to the vibration system components.

Engine Compartment
(10) Forward pressure switch

8. For Early machines, slowly move the propulsion control lever fully forward. For Later machines, remove the cover from pressure switch (10) and place a jumper wire between the C and NO terminals of forward pressure switch (10). Note the reading on the flow meter. The reading should be less than 1.5 liter/min (.40 U.S. gpm).

10. Repeat Steps 6 through 9 to check the reading again.

11. If both readings are more than 1.5 liter/min (.40 U.S. gpm), the vibration motor needs replacement or repair.

12. Stop the engine. Remove flow meter (7) and hose (6). Connect hose (8) to the case return line port of motor (3) again.

NOTE: The compactor's efficiency is directly affected by motor leakage. Maximum frequency, with the engine at full rpm and the compactor at maximum nominal amplitude position, must be a minimum of 2280 vpm in the single drum vibratory mode. In the dual drum mode, the maximum frequency must be a minimum of 2180 vpm.

Vibration Control Pressure Switch Adjustment

Pressure switches (1) and (2) are used to control the speed at which the vibration starts and stops. The switch is set to close at 1.7 mph.

Engine Compartment
(1) Forward pressure switch. (2) Reverse pressure switch.

1. Be sure the engine is stopped and the parking brake is applied.

Rear of Engine
(3) Hose for forward pressure switch. (4) Hose for reverse pressure switch.

2. Install 1P2375 Coupler to the 1U5230 Pump. Install 1P2376 Coupler to one end of the 8F24 Hose Assy. and 8T2352 Swivel Tee to the other end. Install 7X7934 Adapter and 8T855 Gauge, and 6V8934 Reducer to the tee.

3. Disconnect hose (3) or (4) and connect to the reducer on the tee. Install a 6V9828 Cap on the fitting the hose was removed from.

4. Remove the cover from the switch to be tested. Connect the leads from the 6V7800 Digital Multimeter to terminals C and NO.

5. Place the switch on the multimeter to an ohms position.

6. Use the pump to slowly increase the pressure to the switch. When the multimeter shows continuity through the switch, make a note of the gauge reading.

7. The correct pressure is 1075 ± 35 kPa (155 ± 5 psi).

8. If the switch setting is not correct, turn adjusting nut (5) clockwise to increase the pressure setting.

Vibration control pressure switch
(5) Adjustment nut.

9. When the switch setting is correct, remove the test tools. Install the cover on the switch and connect the hose to the fitting it was removed from.