Testing And Adjusting

Usage:

Introduction

Reference: For Specifications with illustrations, refer to the Specifications for the CB-534 Propulsion System, Form No. KENR2420. If the Specifications in Form No. KENR2420 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 propulsion 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 propulsion system, the hydraulic oil must be at the normal temperature for operation.

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

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

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. Stop the engine.

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

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

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

7. Tighten the filler cap on the hydraulic tank.

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

Visual Checks

A visual inspection of the propulsion 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 propulsion system with instruments. Stop the engine, make the following inspections.

1. Check the oil level of the hydraulic tank and the pump splitter box drive.

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

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

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

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

c. Rubber particles give an indication of 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 are damaged.

Checks During Operation

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. Travel speed can be used to check the condition of the propulsion motors and the pump.

Drive the machine backwards and forwards several times. Operate the propulsion controls in all speed ranges.

1. Watch the drive drums. Starting and stopping operations should be progressive. Drum rotation should be smooth and regular at all times.

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

3. Check for the sound of the relief valves opening. The opening pressures of the relief valves are given in the Relief Valves Pressure Tests.

4. After selecting the travel speed of the compactor, the forward and reverse motion should be identical.

Problem: Hydrostatic transmission does not operate in any speed range.

Probable Cause:

1. Low oil pressure caused by:

a. Low oil level in hydraulic tank.

b. Failure of the charge pump.

c. Charge pump relief valve adjustment not correct.

d. Failure of the regulator block.

e. Failure of the direction control valve.

f. Main relief valve adjustment not correct or valve does not close.

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

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

j. Motor piston failure.

k. Plugged hydraulic filter element.

2. Failure of the drive coupling.

3. Failure in the pump splitter box drive.

4. Failure of the brake release and propulsion control lever solenoid valve.

5. Failure of the stop control switch.

Problem: Hydrostatic transmission does not shift from forward to reverse in any speed range.

Probable Cause:

1. Failure of the propulsion control lever valve group.

2. Failure of the regulator block.

3. Failure of the direction control valve.

Problem: Hydrostatic transmission does not shift from reverse to forward in any speed range.

Probable Cause:

1. Failure of the propulsion control lever valve group.

2. Failure of the regulator block.

3. Failure of the direction control valve.

Problem: Hydrostatic transmission engages very slowly when making a shift.

Probable Cause:

1. Low oil level in the hydraulic tank.

2. Plugged filter element in the hydraulic tank.

3. Air entering suction line to the charge pump.

4. Failure of the regulator block.

5. Restriction in flow orifices in the hydraulic regulator.

Problem: Hydrostatic transmission engages very suddenly when making a shift.

Probable Cause:

1. Failure of the regulator block.

Problem: Hydrostatic transmission operates in forward speeds only.

Probable Cause:

1. Broken spring in the propulsion control lever valve group.

2. Failure of the hydraulic regulator.

3. Failure of the direction control valve.

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

5. Main relief valve damaged or incorrectly adjusted in the reverse line of loop circuit.

Problem: Hydrostatic transmission operates in reverse speeds only.

Probable Cause:

1. Broken spring in the propulsion control lever valve group.

2. Failure of the hydraulic regulator.

3. Failure of the direction control valve.

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

5. Main relief valve damaged or incorrectly adjusted in the forward line of loop circuit.

Problem: Hydrostatic transmission does not change speed range when high and low speed range selector switch is moved.

Probable Cause:

1. Fault in the electric circuit.

2. Faulty speed range selector switch.

3. Faulty motor displacement changeover solenoid valve.

4. Faulty propulsion motor displacement changeover spool.

Problem: Hydrostatic transmission does not disengage (zero oil flow) when propulsion control lever is returned to neutral.

Probable Cause:

1. Failure of the direction control valve.

2. Failure of the hydraulic regulator.

3. Incorrect neutral adjustment of the hydraulic regulator.

4. Incorrect neutral adjustment of the direction control valve.

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

6. Failure of the propulsion control valve.

7. Incorrect lever movement adjustment of the propulsion control valve.

Problem: Parking brake does not release when stop control switch is pulled up.

Probable Cause:

1. Failure of the stop control switch.

2. Failure of the charge pump.

3. Charge pump relief valve damaged or incorrectly adjusted.

4. Worn or damaged piston seal in the brake group.

5. Failure of the brake solenoid valve.

6. Fault in the electric circuit.

Problem: Parking brake does not engage when the stop control switch is pushed down.

Probable Cause:

1. Failure of the stop control switch.

2. Worn brake discs.

3. Failure of the brake solenoid valve.

4. Fault in the electric circuit.

Problem: Noisy propulsion motor.

Probable Cause:

1. If the motor gives off a regular humming noise, the shaft bearings are bad.

2. If there is excessive vibration, the retaining bolts are loose.

3. If the motor gives off noise (banging sounds), the charge pump pressure too low.

4. If popping sounds are heard, there is leakage in the motor distributor.

Problem: External oil leaks from propulsion motor.

Probable Cause:

1. Motor case pressure is too high.

2. Restriction in the oil return line to hydraulic tank.

3. Seals damaged due to pressure peaks, use of unapproved hydraulic oil which is not compatible with the seal material or incorrect tightening torque values.

Problem: Hydrostatic circuit oil overheats.

Probable Cause:

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

2. The oil cooler is restricted.

3. Excessive internal leakage in circuit which causes low charge line pressure.

Propulsion System

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.

Method of finding flow loss:

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

Example of finding percent of flow loss:

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

^*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.

Formula I:

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).

Formula II:

Travel Speed 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 speed tests are made with the engine rpm at maximum rpm.

Travel speeds that are the same as those shown in the chart are an indication that the circuit operation is normal. The relief valves for both charge pump and main line closed circuit must be tested to be sure that the opening pressure of each is correct.

If the travel speed is not correct, check the following:

1. Pump efficiency.

2. Setting of the charge pump circuit relief valve.

3. Setting of the main line closed circuit relief valves.

4. Neutral adjustment of the hydraulic regulator.

5. Neutral adjustment of the direction control valve.

6. Make sure the valves and spools in the regulator block and propulsion control lever are not worn.

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) Propulsion pump.

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

3. Start and run the engine at 1500 rpm. Look at the pressure gauge. The relief valve pressure reading should be 2200 ± 110 kPa (320 ± 16 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, 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. 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.

Forward Drive Main Relief Valve Pressure Test
(1) Pressure gauge. (2) Pressure gauge. (3) Manifold block. (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 manifold block (3) from the pump. Install 9S7359 Blocking Plate (4) with an O-ring between manifold block (3) and the pump port.

5. Start and run the engine at 1500 rpm. Place the speed range selector switch in low speed range. Move the travel speed selector to maximum speed position.

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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 propulsion system, do not hold the propulsion control lever in the forward position at relief valve pressure for more than three seconds.

6. Move propulsion control lever fully forward. Look at pressure gauge (2). The relief valve pressure should 42 000 ± 840 kPa (7000 ± 120 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 2200 ± 110 kPa (320 ± 16 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.

7. 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.

8. After the relief valve pressure is adjusted correctly, remove the pressure gauges from pressure taps (5) and (6). Remove the blocking plate and reconnect the manifold block.

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. 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.

Forward Drive Main Relief Valve Pressure Test
(1) Pressure gauge. (2) Pressure gauge. (4) 9S7359 Blocking Plate. (9) Pressure tap. (10) Pressure tap. (11) Manifold block.

3. Connect two 60 000 kPa (9000 psi) pressure gauges (1) and (2) from the 6V4161 Pressure Gauge Kit pressure taps (9) and (10).

4. Disconnect manifold block (11) from the pump. Install 9S7359 Blocking Plate (4) with an O-ring between manifold block (11) and the pump port.

5. Start and run the engine at 1500 rpm. Place the speed range selector switch in low speed range. Move the travel speed selector to maximum speed position.

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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 propulsion system, do not hold the propulsion control lever in the reverse position at relief valve pressure for more than three seconds.

6. Move propulsion control lever fully backward. Look at pressure gauge (2). The relief valve pressure should 42 000 ± 840 kPa (7000 ± 120 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 2200 ± 110 kPa (320 ± 16 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
(12) Locknut. (13) Adjustment screw.

7. If the relief valve pressure is not correct, it must be adjusted. Stop the engine. Loosen locknut (12). Use an allen wrench to turn adjustment screw (13) clockwise to increase the pressure or counterclockwise to decrease the pressure.

8. After the relief valve pressure is adjusted correctly, remove the pressure gauges from pressure taps (9) and (10). Remove the blocking plate and reconnect the manifold block.

Hydraulic Regulator Neutral Adjustment

Oil from the charge pump circuit is used to pilot the hydraulic regulator which controls the swashplate angle of the variable 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. 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
(1) Hose. (2) Port. (3) Port. (4) Locknut. (5) Piston rod adjustment screw. (6) Pressure tap. (7) Pressure tap.

3. Connect hose (1) between ports (2) and (3). This will ensure equal oil pressure 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 (6) and (7).

5. Start and run the engine at 1500 rpm.

6. Place the speed range selector switch in low speed range.

7. Move the travel speed selector to the minimum speed position.

8. Move the propulsion control lever to neutral position.

9. Look at the pressure gauges. Both readings should be the same.

10. If it is necessary to adjust the neutral position of the piston, loosen locknut (4). Use an allen wrench to turn piston rod adjustment screw (5). Turn the screw clockwise or counterclockwise depending on the spool movement requirement. The pressures on the gauges should change. Adjust screw (5) until they are the same.

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

12. Repeat Steps 5 through 10.

13. Tighten locknut (4). Remove the pressure gauges, hoses and connectors from pressure taps (6) and (7). Remove the hose from ports (2) and (3).

Direction Control Valve Neutral Adjustment

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

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
(1) Pressure tap. (2) Pressure tap. (3) Locknut. (4) Centering screw.

3. Connect two 4000 kPa (600 psi) pressure gauges from the 6V4161 Pressure Gauge Kit to pressure taps (1) and (2).

4. Place the speed range selector switch in low speed range.

5. Move the travel speed selector to the minimum speed position.

6. Move the propulsion control lever to the neutral position.

7. Start and run the engine at 1500 rpm. Look at the test gauges. Both readings should be identical.

8. If it is necessary to adjust the neutral position of the valve, loosen locknut (3). Use an allen wrench to turn centering screw (4) clockwise or counterclockwise depending on spool movement requirement. The pressures on the gauges should change. Adjust screw (4) until they are identical.

9. Tighten locknut (3). Remove the pressure gauges and hoses from pressure taps (1) and (2).

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

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

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Before filtering the circuit, refer to the WARNING on the first page of Troubleshooting.

Dual Filter Procedure

Closed Circuit Loop Line Filtration Diagram
(1) Hydraulic tank. (2) Filter. (3) Propulsion pump. (4) Manifold block. (5) Filter. (6) Front motor loop circuit return line for forward drive. (7) Rear motor loop circuit return line for forward drive. (8) Rear motor high pressure loop circuit line for forward drive. (9) Front motor high pressure loop circuit line for forward drive.

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To prevent personal injury, use lifting equipment or a method to safely lift the machine until the drums are off the ground. Put wood blocks or jack stands of the correct capacity under the machine to hold it in position while the following procedure is performed.

1. Install the frame articulation lock pin. Raise the machine until the drums are off the ground. Put wood blocks or jack stands of the correct capacity under the front and rear side frames. Position the wood blocks or jack stands so they are in line with the holes in the side frames which are used for lifting the machine. This will allow the drums to rotate without machine movement.

2. Disconnect front motor hose (6) from manifold block (4) on pump (3). Install filter (5) between manifold block (4) and hose (6). Make sure that the arrow on the filter is pointing in the same direction as the flow of oil from the pump.

3. Disconnect rear motor hose (7) from manifold block (4) on pump (3). Install second filter (2) between manifold block (4) and hose (7). Make sure that the arrow on the filter is pointing in the same direction as the flow of oil from the pump.

4. Start and run the engine at 1500 rpm. Select first speed range. Move travel speed selector to maximum travel speed position.

5. Release the brakes by pulling the stop control upward. Move the propulsion control lever fully forward. Filter the circuit for a period of 5 minutes.

Single Filter Procedure

If only one filter is available, it will be necessary to isolate the front motor loop circuit from the rear circuit. The motors' oil supply is in parallel. Separating the circuits will ensure that all the oil flow from the pump will pass through the filter.

Closed Circuit Loop Line Filtration Diagram
(1) Hydraulic tank. (3) Propulsion pump. (4) Manifold block. (5) Filter. (6) Front motor loop circuit return lien for forward drive. (7) Rear motor loop circuit return line for forward drive. (8) Rear motor high pressure loop circuit line for forward drive. (9) Front motor high pressure loop circuit line for forward drive. (10) 9S7359 Blocking Plates. (11) Manifold block.

1. Disconnect rear motor loop circuit hoses (7) and (8) from manifold blocks (4) and (11). Install 9S7359 Blocking Plate (10) with an O-ring between each hose and manifold block. Reconnect the hose.

3. Start and run the engine at 1500 rpm. Select first speed range. Move travel speed selector to maximum travel speed position.

4. Release the brakes by pulling the stop control upward. Move the propulsion control lever fully forward. Filter the circuit for a period of 5 minutes.

5. Remove filter (5) and blocking plates (10). Reconnect all of the hoses again.

6. Disconnect from motor loop circuit hoses (6) and (9) from manifold blocks (4) and (11). Install blocking plate (10) with an O-ring between each hose and manifold block. Reconnect the hoses.

7. Disconnect rear motor hose (7) from manifold block (4) on pump (3). Install a filter between manifold block (4) and hose (7). Make sure that the arrow on the flter is pointing in the same direction as the flow of oil from the pump.

8. Start and run the engine at 1500 rpm. Select first speed range. Move travel speed selector to maximum travel speed position.

9. Release the brakes by pulling the stop control upward. Move the propulsion control lever fully backward. Filter the circuit for a period of 5 minutes.

10. Remove the filter and blocking plates (10). Reconnect all of the hoses again.

Hydraulic Motor Leakage Tests

A certain amount of internal leakage is needed for lubrication in the hydraulic motors. Leakage above the allowed valve 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.

Two different test must be done to determine the cause of the internal leakage.

Static Test For Distributor And Piston Leakage Between Supply Line And Motor Case

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Refer to the WARNING on the first page of Troubleshooting.

When doing a hydraulic leakage test, the brake release hoses must be disconnected from motors. This will allow the brakes to remain engaged during the test.

1. Disconnect the brake hoses. Plug the hoses with 813400 Connectors and 814072 Plugs. Also install 814072 Plugs in each motor port.

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

3. Use the main relief valve to decrease the pressure in the supply line to 30 000 ± 600 kPa (4350 ± 88 psi). Refer to Main Relief Valve Pressure Test in Testing And Adjusting.

Front Propulsion Motor Leakage Test
(1) Hydraulic tank. (2) Front motor return line hose. (3) Flow meter. (4) Hose. (5) Front propulsion motor. (6) Rear propulsion motor. (7) Rear motor return line hose. (8) Propulsion pump.

4. Disconnect front motor case tank return line hose (2) from front motor (5).

5. Connect 812396 Hose (4) to the inlet port of flow meter (3). Connect return line hose (2) to the outlet port of flow meter (3). Connect hose (4) to the outlet port on motor (5).

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NOTICE

To prevent overheating the oil, do not do each test longer than 15 seconds.

6. Start and run the engine at 2230 rpm. Select first speed range. Move the travel speed selector to the maximum travel speed position. Pull the stop control upwards.

7. Slowly move the propulsion control lever fully forwards. Forward movement of the control lever will cause pressure oil to leave the pump through outlet port at the bottom of the pump. Movement of the control lever in the reverse direction will cause pressure oil to flow from the pump through the top outlet port.

8. Note the reading on flow meter (3). The maximum permissable leakage allowed for a motor in service is as follows:

Forward drive:

Large displacement (low speed range) ... 3 liter/min(.8 U.S. gpm)

Small displacement (high speed range ... 2.5 liter/min(.66 U.S. gpm)

Reverse drive:

Large displacement (low speed range) ... 2.9 liter/min(.77 U.S. gpm)

Small displacement (high speed range) ... 3.9 liter/min(1.03 U.S. gpm)

9. Do the test again and compare the readings. Each test must not last for more than 15 seconds, otherwise the temperature of the oil will rise.

NOTE: The front propulsion motor leakage test is illustrated in this procedure. To test the rear drum propulsion motor, disconnect return line hose (7) and connect flow meter (3) and hose (4) between the return line hose and rear propulsion motor (6). Repeat Steps 6 through 9.

10. Since only four of the motor pistons are connected to the supply line at a given time, it will be necessary to change the combination of pistons which are active. To do this, the hydraulic motor which is being tested will have to be moved a third of a turn.

11. Remove the plugs in the brake hoses and motor ports. Reconnect the brake hoses to the motors.

12. Mark the outside of the drum with chalk evenly spaced at 120°. Start the engine and move the machine forward for a distance which is equal to one third of a turn of the drum.

13. Repeat Steps 3 through 9. Record the reading for this set of four pistons.

14. To test the last set of four pistons in the motor, repeat Steps 10 through 13.

15. Compare the three readings. The values should be identical. If they are not, it indicates that there is damage or wear to this particular group of pistons. If all of the readings are greater than the maximum allowed leakage, there is damage or wear to the distributor and/or all of the pistons.

Brake Efficiency Check

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Refer to the WARNING on the first page of Troubleshooting.

When doing a brake efficiency check, the brake release hose must be disconnected from each motor. This will keep the brakes engaged during this check.

Brake Efficiency Check
(1) Brake release hose. (2) Front propulsion motor. (3) Brake release ports. (4) Rear propulsion motor.

1. Disconnect brake release hose (1) from front propulsion motor (2) and rear propulsion motor (4). Plug both ends of the hose with 813400 Connectors and 814072 Plugs. Plug brake release port (3) of each motor with 814072 Plugs.

Pressure Taps
(5) Pressure tap. (6) Pressure tap.

2. Connect a 60 000 kPa (9000 psi) pressure gauge from the 6V4161 Pressure Gauge Kit to pressure tap (5) at the pump.

3. Connect a 25 000 kPa (4000 psi) pressure gauge from the 6V4161 Pressure Gauge Kit to pressure tap (6) at the pump.

4. Start and run the engine at 1500 rpm. Place the speed range selector switch in low speed range. Move the travel speed selector to the maximum speed position.

5. Pull the stop control upwards. Move the propulsion control lever fully forward.

6. As soon as drum starts to turn, note the pressure gauge readings. The pressure difference between the two gauges (difference between the supply line and the return line of the loop circuit) must not be less than 35 000 ± 700 kPa (5100 ± 100 psi).

7. Use the main relief valve to increase the pressure in the supply line if the pressure is not high enough to rotate drum.

8. If the pressure difference between the two gauges is less than 35 000 ± 700 kPa (5100 ± 100 psi), this indicates that the brake discs are worn and need to be replaced.

New Propulsion Motor Startup Procedure

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Refer to the WARNING on the first page of Troubleshooting.

1. Whenever a new propulsion motor is installed, the hydraulic circuit must be completely flushed through before starting the machine.

2. When refilling the circuit with new oil, remove the breather/filler cap on the hydraulic tank and fill only through the strainer. The total circuit capacity is 90 liters (23.4 U.S. gallons).

3. To make sure the motor cases are completely full of oil, position the propulsion motor so that bleed plug is at its uppermost level. Remove the bleed plug on each motor. Once the motor cases are full of oil, install the bleed plugs again.

Show/hide table

4. Install the frame articulation lock pin. Raise the machine until the drums are off the ground. Put wood blocks or jack stands of the correct capacity under the front and rear side frames. Position the wood blocks or jack stands so they are in line with the holes in the side frames which are used for lifting the machine.

5. Do the filtration procedure as shown in Closed Circuit Loop Line Filtration in Testing And Adjusting.

6. If the machine has front and rear drum brake systems, the brake release hose to the motor which is not being tested must be disconnected at the motor port. Plug the hose with an 813400 Connector and an 814072 Plug. Also, install an 814072 Plug in the brake release port of the motor.

Pressure Gauge Installation
(1) Motor leakage return line to tank. (2) Brake pilot line pressure tap. (3) Closed circuit pressure tap. (4) Closed circuit pressure tap.

Pressure Gauge Installation
(5) Pressure tap. (6) Propulsion pump.

7. Connect two 60 000 kPa (9000 psi) gauges from the 6V4161 Pressure Gauge Kit to pressure taps (3) and (4) of the propulsion pump.

8. Connect a 4000 kPa (600 psi) pressure gauge from the 6V4161 Pressure Gauge Kit with 812995 Union and a 814543 Connector to pressure tap (2) for the brake circuit check.

9. Connect another 4000 kPa (600 psi) pressure gauge from the 6V4161 Pressure Gauge Kit with a 814227 Union and a 814543 Connector to motor case tank return line hose (1) as shown.

10. Connect another 4000 kPa (600 psi) pressure gauge from the 6V4161 Pressure Gauge Kit to propulsion pump case return pressure tap (5) at the top of propulsion pump (6).

No Load Test

1. Start and run the engine at 1500 rpm. Select first speed range. Move travel speed selector to position which corresponds to about 10 to 20% of nominal travel speed.

2. Release the brakes by pulling the stop control upwards. Move the propulsion control lever fully forward.

3. Check for any external oil leakage in the system. Check motor case pressure at the gauge in return line hose (1). The maximum allowable pressure when the oil is cold is 300 kPa (44 psi). If the pressure is too high, there is a restriction in the return circuit.

4. Check the closed circuit return loop line pressure at pressure taps (3) and (4). Check this pressure in both forward and reverse. Both of these pressures should be 2200 ± 110 kPa (320 ± 16 psi). If either of these pressures is too low, there is too much leakage in that motor. See Hydraulic Motor Leakage Tests in Testing And Adjusting.

Load Test

1. Bring the motors up to operating rotational speed and pressure.

2. Check for any external oil leakage in the system. Check motor case pressure at the gauge in return line hose (1). The maximum allowable pressure when the oil temperature has reached 50 to 60°C (122 to 140°F) is 150 kPa (22 psi). The circuit temperature should not exceed 80°C (176°F). If the pressure is too high, there is a restriction in the return circuit.

3. Check the cooling circuit return pressure at pressure tap (5) at the top of propulsion pump (6). The cooling circuit return pressure should be a maximum of 200 ± 10 kPa (29 ± 1.5 psi). If the pressure is too high, there is a restriction in the oil cooler.

4. Check the brake circuit pressure at pressure tap (2). The pressure should be 2200 ± 110 kPa (320 ± 16 psi). If the pressure is too high, there is a restriction in the brake circuit.