Troubleshooting
PROBLEM 1: System response is sluggish.
PROBABLE CAUSE:
Poor system response could be caused by low hydraulic pressure in the system, or by a mechanical problem in the front gear reducer, rear propel motor, axle, or drum.
1. Check the level of oil in the hydraulic oil tank. Add oil if it is low. Check the lines, hoses, connections, and components for leaks.
2. Check for abnormally low charge pressure.
3. Check/relief valves in pump may be stuck open.
4. Shuttle valve spool or relief valve in cooling and test manifold may be stuck.
5. Check for internal damage to front gear reducer or rear propel motor.
6. Check for damage to end reduction case, carrier, or wheel end assemblies
7. Check for damage to drum support assembly on vibratory side of drum.
PROBLEM 2: Machine does not propel in either direction.
PROBABLE CAUSE:
This may be caused by damage to the double-pump drive, a broken pump input shaft, or internal damage to the propel pump. Other possible causes are broken control linkage to propel pump, loss of charge pressure, or low hydraulic oil level.
1. Check control cable linkage from propel lever to propel pump. Make sure connections are secure and propel lever operates smoothly.
2. Check the level of oil in the hydraulic oil tank. Add oil if it is low. Check the lines, hoses, connections, and components for leaks.
3. Check for abnormally low charge pressure
4. Check for damage to propel pump.
5. Check for damage to double-pump drive.
PROBLEM 3: System operates in one direction only.
PROBABLE CAUSE:
This could occur if the shuttle valve spool was stuck in one position, if the control linkage was broken, or if there was internal damage to the propel pump.
1. Check operation of shuttle valve spool in cooling and test manifold.
2. Check control cable linkage from propel lever to propel pump. Make sure connections are secure and propel lever operates smoothly.
3. Check for internal damage to propel pump.
PROBLEM 4: Speed does not shift when speed range shift switch is moved.
PROBABLE CAUSE:
This could be caused by internal damage to front gear reducer or rear propel motor or by failure of the shift valve.
1. Check for correct shift pressure at front gear reducer and rear propel motor.
2. Check operation of shift valve.
3. Check for internal damage to front gear reducer or rear propel motor.
4. Check five amp fuse on instrument panel.
5. Check electrical wiring for shorts or damaged components.
PROBLEM 5: Machine moves when propel lever is in STOP position.
PROBABLE CAUSE:
This could occur if the control cable was out of adjustment at the propel lever, or if the linkage between the propel pump control handles was out of adjustment.
1. Check control cable linkage from propel lever to propel pump. Make sure connections are secure and propel lever operates smoothly.
2. Check synchronization of propel pump control handles.
3. Remove and inspect the pump for damaged parts or incorrect assembly.
PROBLEM 6: 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 propel pump. If any are 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 propel pump charge pressure. Loss of charge pressure can cause excessive heat build-up in the system.
PROBLEM 7: 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 propel 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.
6. Check engine rpm at full throttle. If the engine is not operating at rated rpm, pump output will be reduced.
PROBLEM 8: 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 internal leakage in hydraulic components may be hard to see.
2. Check the operation of the check/relief valves in the pump.
3. Check the operation of the shuttle valve and relief valve in the cooling and test manifold.
4. Remove and inspect the pump for damage and correct assembly.
5. Remove and inspect front gear reducer for broken parts.
6. Check rear propel motor, axle assembly, and wheel end assemblies for broken parts.
PROBLEM 9: Oil pressure in the system is too high.
PROBABLE CAUSE:
Excessive oil pressure in the system can be caused by binding or high mechanical friction in the drive components. Parts could be broken in the front gear reducer, rear propel motor, axle assembly, wheel end assemblies, or drum.
1. Remove and inspect front gear reducer for broken parts.
2. Check rear propel motor, axle assembly, and wheel end assemblies for broken parts.
3. Check for damage to drum support assembly on vibratory side of drum.
4. Drum scraper(s) set too close to drum.
5. Check the secondary/parking brake system for a possible problem.
PROBLEM 10: 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 damaged drive components.
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 operation of check/relief valves in pump.
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. Remove and inspect front gear reducer for broken parts.
8. Check rear propel motor, axle assembly, and wheel end assemblies for broken parts.
PROBLEM 11: Machine seems to lug down when propelling on level ground.
PROBABLE CAUSE:
Front section and rear section of propel pump are not synchronized.
1. Perform the system pressure tests in this module.
2. Adjust propel linkage at pumps.
3. Check pump output to determine if pump is worn out.
4. Check for contamination in cooling and test manifold - internal orifices must be clear.
Test Procedures
 |
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. |
 |
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 propel system, perform the Visual Checks first. Then do the Control Response Test and Shift Test. If these checks indicate a problem in the system, perform the other tests and adjustments as necessary to identify and solve the problem.
|
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. |
|
|
To prevent possible personal injury, when tests are made with the machine moving, make sure only one operator is on the machine. Keep other personnel away from the machine. Make sure tests are done in a flat and open area. |
|
|
Do not check for leaks with your hands. Pin hole (very small) leaks can result in a high velocity oil steam 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 holes. |
|
Reference: Be sure to follow correct safety practices when performing procedures covered in this module. See Safety Page, Form No. SENR7733.
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.
Control Response Test
|
This test should be performed on a hard, level surface. Be prepared for very rapid stops. Clear area in direction of machine travel. |
|
1. Start engine following proper operating procedures. Run engine at full throttle.
2. Release the secondary/parking brake.
3. Set speed range shift switch in HIGH position.
4. Slowly move propel lever to full FORWARD position. Machine should propel smoothly and quickly to full speed.
5. Check the "feel" of the machine. Drum and rear wheels should propel the machine equally.
6. Move propel lever back to the STOP position. The propel pump should respond within 1 1/2 seconds, and the machine should stop quickly.
7. Slowly move propel lever to full reverse position. Machine should propel smoothly and quickly to full speed.
8. Move propel lever back to the STOP position. The propel pump should respond within 1 1/2 seconds, and the machine should stop quickly.
9. If machine response is sluggish, or if propel system "feels" wrong, there may be a problem in the propel system. Refer to Troubleshooting, and the following Tests and Adjustments to find and correct the problem.
Shift Test
Reference: Be sure to follow proper operating procedures when shifting from HIGH to LOW when machine is moving. See Operation and Maintenance manual, Form No. KEBU2846.
1. Start engine and run at full throttle.
2. Release secondary/parking brake.
3. Set speed range shift switch in LOW position.
4. Slowly move propel lever to full FORWARD position to propel machine at full speed.
5. Move speed range shift switch to HIGH position.
6. Front gear reducer and rear propel motor should both shift to HIGH speed range. The machine should increase speed.
7. Move propel lever to 1/2 FORWARD or less.
8. Move speed range shift switch to LOW position.
9. Front gear reducer and rear propel motor should both shift to LOW speed range. The machine should decrease speed.
10. Move propel lever back to the STOP position.
11. If front gear reducer and rear propel motor do not shift when speed range shift switch is moved, there is a problem in the system. Refer to Troubleshooting. See Speed Range Shift Check in this module.
System Pressure Test (Forward)
System pressure in the drum propel loop should be equal to system pressure in the rear wheel propel loop. Perform the following steps to check system pressure in the two loops while driving the machine forward.
NOTE: This test should be performed on a hard, level surface. Clear area in direction of machine travel.
Test Port Locations
(1) Test port X5. (2) Test port X7.
1. Install a 0 to 41 400 kPa (0 to 6000 psi) pressure gauge with a hose and quick disconnect fitting, to test port X5 (1). This gauge will measure hydraulic pressure in the drum propel loop.
2. Install a 0 to 41 400 kPa (0 to 6000 psi) pressure gauge with a hose and quick disconnect fitting, to test port X7 (2). This gauge will measure hydraulic pressure in the rear wheel propel loop.
3. Secure the two gauges to the arm of operator's seat. Mark the gauges X5 and X7, so the operator can read the gauges while driving the machine.
4. Start engine and run at full throttle.
5. Release secondary/parking brake.
6. Set speed range shift switch in HIGH position.
7. Slowly move propel lever to full FORWARD position to propel machine at full speed.
8. Observe the readings on pressure gauges X5 and X7. Both gauges should read approximately 10 300 to 11 700 kPa (1500 to 1700 psi).
9. Move propel lever back to the STOP position. Shut engine OFF.
10. Record the pressure readings from step 8 on the following table.
11. Relief valve setting in propel pump is 30 000 kPa (4350 psi). If either pressure gauge reading is at relief setting, pressure is too high. Check front gear reducer, rear propel motor, or axle assembly for broken parts.
12. If either pressure gauge reading is less than 6900 kPa (1000 psi) there may be a problem in the system. Refer to Troubleshooting.
13. If drum and wheel pressure readings differ by more than 1380 kPa (200 psi), the propel pump may need adjustment. Perform Control Rod Length Adjustment and Pump Synchronization Adjustment in this module.
14. If system pressure at both gauges is too low, the shuttle valve spool in cooling and test manifold may be stuck. Otherwise, the pump output may be insufficient.
15. Keep the recorded readings from pressure gauges X5 and X7. Perform System Pressure Test (Reverse) located in this module.
System Pressure Test (Reverse)
System pressure in the drum propel loop should be equal to system pressure in the rear wheel propel loop. Perform the following steps to check system pressure in the two loops while driving the machine in reverse.
NOTE: This test should be performed on a hard, level surface. Clear area in direction of machine travel.
Test Port Locations
(1) Test port X6. (2) Test port X8.
1. Install a 0 to 41 400 kPa (0 to 6000 psi) pressure gauge with a hose and quick disconnect fitting, to test port X8 (2). This gauge will measure hydraulic pressure in the drum propel loop.
2. Install a 0 to 41 400 kPa (0 to 6000 psi) pressure gauge with a hose and quick disconnect fitting, to test port X6 (1). This gauge will measure hydraulic pressure in the rear wheel propel loop.
3. Secure the two gauges to the arm of operator's seat. Mark the gauges X8 and X6, so the operator can read the gauges while driving the machine.
4. Start engine and run at full throttle.
5. Release secondary/parking brake.
6. Set speed range shift switch in HIGH position.
7. Slowly move propel lever to full REVERSE position to propel machine at full speed.
8. Observe the readings on pressure gauges X8 and X6. Both gauges should read approximately 10 300 to 11 700 kPa (1500 to 1700 psi).
9. Move propel lever back to the STOP position. Shut engine OFF.
10. Record the pressure readings from step 8 on the following table.
11. Relief valve setting in propel pump is 30 000 kPa (4350 psi). If either pressure gauge reading is at relief setting, pressure is too high. Check front gear reducer, rear propel motor, or axle assembly for broken parts.
12. If either pressure gauge reading is less than 6900 kPa (1000 psi) there may be a problem in the system. Refer to Troubleshooting and the following steps.
13. If drum and wheel pressure readings differ by more than 1380 kPa (200 psi), the propel pump may need adjustment. Perform Control Rod Length Adjustment and Pump Synchronization Adjustment in this module.
14. If system pressure at both gauges is too low, the shuttle valve spool in cooling and test manifold may be stuck. Otherwise, the pump output may be insufficient.
- a. Low charge pressure. See Charge Pressure Test in this module.
- b. Propel pump sections not synchronized. See Pump Synchronization Adjustment and Control Rod Length Adjustment in this module.
- c. Insufficient output from front section of propel pump (closest to double-pump drive). See Pump Efficiency Test in this module.
- d. Damage to front gear reducer.
- b. Propel pump sections not synchronized. See Pump Synchronization Adjustment and Control Rod Length Adjustment in this module.
15. Compare the recorded drum loop pressures from test ports X5 and X8. If both are too low, check the following possible causes.
16. If just one pressure reading is low, look for a damaged check/relief valve in the propel pump, or a problem in the cooling and test manifold.
- a. Low charge pressure. See Charge Pressure Test in this module.
- b. Propel pump sections not synchronized. See Pump Synchronization Adjustment and Control Rod Length Adjustment in this module.
- c. Insufficient output from rear section of propel pump (farthest from double-pump drive). See Pump Efficiency Test in this module.
- d. Damage to rear propel motor or axle assembly.
- b. Propel pump sections not synchronized. See Pump Synchronization Adjustment and Control Rod Length Adjustment in this module.
17. Compare the recorded rear wheel loop pressures from test ports X7 and X6. If both are too low, check the following possible causes.
18. If just one pressure reading is low, look for a damaged check/relief valve in the propel pump, or a problem in the cooling valve.
Charge Pressure Test
Check charge pressure if the propel system is sluggish or does not respond well to the controls. If charge pressure is too low, pump output may be poor. Pressure in both propel loops may be low, especially when demand on the system is high (traveling up a grade or on rough ground).
Test Port Locations
(1) Test port X3.
1. Remove cap from test port X3 (1) behind operator's seat. Install a 0 to 4100 kPa (0 to 600 psi) pressure gauge with a hose and quick disconnect fitting.
2. Secure the gauge to the arm of operator's seat, so the operator can read the gauge while driving the machine.
3. Start engine and run at full throttle.
4. Observe pressure gauge. Record charge pressure reading on the following table.
5. Release secondary/parking brake.
6. Set speed range shift switch in HIGH position.
7. Slowly move propel lever to full FORWARD position to propel machine at full speed.
8. Observe pressure gauge. Record charge pressure reading on the following table.
9. Move the propel lever back to the STOP position.
10. Apply secondary/parking brake. Shut engine OFF.
11. The recorded charge pressures should be approximately 1655 to 2140 kPa (250 to 310 psi) in both boxes in the above table.
- a. If charge pressure while standing still is too low, the charge pump may be damaged or not getting enough oil.
- b. If charge pressure drops while propelling, the propel pump may be damaged or there may be excessive leakage in one of the closed-loops.
12. If either of the recorded charge pressures is less than 1380 kPa (200 psi), check the following.
Pump Efficiency Tests
Do these tests if System Pressure Test indicates low system pressure in the drum propel loop or in the rear wheel propel loop. Perform the first test below to check the front section of propel pump. Front section of pump provides pressure to the drum propel loop. Perform the second test below to check the rear section of propel pump. Rear section of pump provides pressure to the rear wheel propel loop.
Front Section of Pump (Drum Propel Loop)
Propel Pump
(1) Hydraulic hose to front gear reducer. (2) Hydraulic hose to front gear reducer. (3) Forward pressure port. (4) Reverse pressure port. (5) Pressure port to cooling and test manifold. (6) Hydraulic hose to cooling and test manifold. (7) Hydraulic hose to cooling and test manifold.
1. Go through the floor opening behind operator's seat. Identify the forward pressure port (3), the reverse pressure port (4), and the pressure port to cooling and test manifold (5), located on propel pump.
2. Disconnect two hydraulic hoses (6) and (7) leading from propel pump to cooling and test manifold. Mark the two hoses for reassembly. Install plugs into the hose ends capable of withstanding 41 400 (6000 psi). Cap the fittings on the pump with caps capable of withstanding 41 400 kPa (6000 psi).
3. Disconnect two hydraulic hoses (1) and (2) leading from propel pump to front gear reducer. Mark the two hoses for reassembly. Plug the hose ends to prevent contaminants from entering.
4. Install inlet line of a flow meter to forward pressure port (3). Install outlet line of flow meter to reverse pressure port (4).
5. Open the manual load valve (on flow meter) fully.
6. Raise the entire machine on blocks so rear wheels can rotate without moving machine.
7. Start engine and run at full throttle.
8. Set speed range shift switch in LOW position.
| NOTICE |
|---|
Avoid damage to flow meter. Do not move propel lever to REVERSE position. Read instructions for flow meter before use. |
9. Move propel lever to full FORWARD position.
10. Slowly close the manual load valve (on flow meter) to set system pressure at 11 700 kPa (1700 psi).
11. Observe flow meter. Record pump output reading.
12. Shut engine OFF. Ensure all hydraulic pressure is removed from the system. Disconnect flow meter.
13. Install inlet line of flow meter to reverse pressure port (4). Install outlet line of flow meter to forward pressure port (3).
14. Open the manual load valve (on flow meter) fully.
15. Start engine and run at full throttle.
| NOTICE |
|---|
Avoid damage to flow meter. Do not move propel lever to FORWARD position. Read instructions for flow meter before use. |
16. Move propel lever to full REVERSE position.
17. Slowly close the manual load valve (on flow meter) to set system pressure at 11 700 kPa (1700 psi).
18. Observe flow meter. Record pump output reading.
19. Shut engine OFF. Ensure all hydraulic pressure is removed from the system. Disconnect flow meter.
20. Reinstall hydraulic hoses (6), (7), (1), and (2) to propel pump.
21. Pump output should be approximately 114 liter/min (30 U.S. gpm) in both forward and reverse.
22. If pump output is less than 95 liter/min (25 U.S. gpm) in either direction, refer to Troubleshooting for probable cause and remedy.
Rear Section of Pump (Rear Wheel Propel Loop)
Propel Pump
(1) Hydraulic hose to rear propel motor. (2) Reverse pressure port. (3) Forward pressure port. (4) Hydraulic hose to rear propel motor. (5) Pressure port to cooling and test manifold. (6) Hydraulic hose to cooling and test manifold. (7) Hydraulic hose to cooling and test manifold.
1. Go through floor opening behind operator's seat. Identify the forward pressure port (3), the reverse pressure port (2), and the pressure port to cooling and test manifold (5), located on propel pump.
2. Disconnect two hydraulic hoses (6) and (7) leading from propel pump to cooling and test manifold. Mark the two hoses for reassembly. Install plugs into the hose ends capable of withstanding 41 400 kPa (6000 psi). Cap the fittings on the pump with caps capable of withstanding 41 400 kPa (6000 psi).
3. Disconnect two hydraulic hoses (1) and (4) leading from propel pump to rear propel motor. Mark the two hoses for reassembly. Plug the hose ends to prevent contaminants from entering.
4. Install inlet line of a flow meter to forward pressure port (3). Install outlet line of flow meter to reverse pressure port (2).
5. Open the manual load valve (on flow meter) fully.
6. Raise the entire machine on blocks so drum can rotate without moving machine.
7. Start engine and run at full throttle.
8. Set speed range shift switch in LOW position.
9. Release secondary/parking brake.
| NOTICE |
|---|
Avoid damage to flow meter. Do not move propel lever to REVERSE position. Read instructions for flow meter before use. |
10. Move propel lever to full FORWARD position.
11. Slowly close the manual load valve (on flow meter) to set system pressure at 11 700 kPa (1700 psi).
12. Observe flow meter. Record pump output reading.
13. Shut engine OFF. Ensure lll hydraulic pressure is removed from the system. Disconnect flow meter.
14. Install inlet line of flow meter to reverse pressure port (2). Install outlet line of flow meter to forward pressure port (3).
15. Open the manual load valve (on flow meter) fully.
16. Start engine and run at full throttle.
| NOTICE |
|---|
Avoid damage to flow meter. Do not move propel lever to FORWARD position. Read instructions for flow meter before use. |
17. Move propel lever to full REVERSE position.
18. Slowly close the manual load valve (on flow meter) to set system pressure at 11 700 kPa (1700 psi).
19. Observe flow meter. Record pump output reading.
20. Shut engine OFF. Ensure all hydraulic pressure is removed from the system. Disconnect flow meter.
21. Reinstall hydraulic hoses (6), (7), (1), and (4) to propel pump.
22. Pump output should be approximately 114 liter/min (30 U.S. gpm) in both forward and reverse.
23. If pump output is less than 95 liter/min (2.5 U.S. gpm) in either direction, refer to Troubleshooting for probable cause and remedy.
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. Set a flow meter on operator's seat. Run flow meter lines through floor opening behind operator's seat, to cooling and test manifold.
3. Install inlet line of flow meter to port T (1). Install outlet line of flow meter to hydraulic return line (2).
4. Open manual load valve (on flow meter) fully.
5. Start engine and run at full throttle.
6. Observe and record the flow meter reading with propel lever in the STOP position.
7. Release secondary/parking brake.
8. Set speed range shift switch in LOW position.
9. Slowly move propel lever to full FORWARD position to propel machine at full speed.
10. Observe and record the flow meter reading.
11. Slowly move propel lever first to STOP, then back in the full REVERSE position to propel the machine at full speed.
12. Observe and record the flow meter reading.
13. Move propel lever to STOP position. Shut engine off.
14. Flow meter should read zero when propel lever is in STOP position. Flow meter should read approximately 72 liter/min (19 U.S. gpm) in both forward and reverse operation.
15. 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 propel system, and one set is for the vibratory 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.
Valve Cartridges
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 propel system, and one is for the vibratory 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.
Speed Range Shift Check
Perform this check if the machine does not shift correctly, or if machine operates all right in one speed range, but not in the other.
1. Raise the entire machine on blocks so drum and rear wheels can rotate without moving machine.
2. Start engine and run at full throttle.
3. Release secondary/parking brake.
4. Set speed range shift switch in LOW position.
5. Move propel lever to full FORWARD position. Drum and rear wheels should rotate at LOW speed.
6. Move speed range shift switch to HIGH position.
7. Observe drum and rear wheels. Front gear reducer and rear propel motor should both shift to HIGH speed range. Drum and rear wheels should rotate faster.
8. Move propel lever to 1/2 FORWARD or less.
9. Move speed range shift switch back to LOW.
10. Front gear reducer and rear propel motor should both shift to LOW speed range. Drum and rear wheels should rotate more slowly.
11. If front gear reducer and/or rear propel motor do not shift properly, perform the Shift Pressure Test procedure in this module.
Shift Pressure Test
Front Gear Reducer
(1) Shift hydraulic hose.
Rear Propel Motor
(2) Shift hydraulic hose.
1. Disconnect shift hydraulic hose from front gear reducer (1) or rear propel motor (2).
2. Cap fitting on front gear reducer or rear propel motor to prevent dirt from entering.
3. Install a 0 to 4100 kPa (0 to 600 psi) pressure gauge to the shift hydraulic hose (1) or (2) for the front gear reducer or rear propel motor (whichever is being tested).
4. Start engine and run at full throttle.
5. Set speed range shift switch in LOW position. Pressure gauge should read 0.
6. Move speed range shift switch to HIGH. Pressure gauge should indicate approximately 1655 to 2140 kPa (250 to 310 psi).
7. If correct pressure is indicated on gauge in steps 5 and 6 but front gear reducer or rear propel motor is stuck in HIGH or LOW, the front gear reducer or rear propel motor needs to be repaired.
8. If pressure gauge reading in step 5 or step 6 is not correct, shift valve may be damaged. See Shift Valve Electrical Test in this module.
Reference: Low shift pressure could be caused by low charge pressure in the propel pump. See Charge Pressure Test in this module.
Shift Valve Electrical Test
If moving the speed range shift switch does not cause front gear reducer and rear propel motor to shift speed range, check electrical wiring to the shift valve as follows.
Shift Valve
(1) Wire. (2) Ground screw. (3) Wire. (4) Coil.
1. Check the five amp fuse on instrument panel. Replace if necessary. If fuse blows frequently, determine cause as follows and repair.
- a. With keyswitch in the OFF position, touch the leads of an ohmmeter to wires (1) and (3). Electrical resistance should be 8 ohms. If not, coil (4) must be replaced.
- b. Check electrical wiring from wire (3) to the five amp fuse, for electrical shorts. Repair or replace damaged wiring or components.
2. With keyswitch in the OFF position, touch the leads of an ohmmeter to wires (1) and (3). Electrical resistance should be 8 ohms. If not, coil (4) must be replaced.
3. Make sure wire (1) is connected to ground screw (2). Secure ground connection if necessary.
4. Attach the leads of a voltmeter to wires (1) and (3). Turn keyswitch to the ON position. Set speed range shift switch to LOW. Voltmeter should read zero.
5. If voltmeter does not read zero, speed range shift switch should be checked, and replaced if necessary.
6. Set speed range shift switch to HIGH. Voltmeter should read approximately 12 volts.
7. If voltmeter reads 12 volts, but shift valve does not work, the shift valve should be repaired or replaced.
8. If voltmeter does not read 12 volts, check whether 12 volts is available at the speed range shift switch.
9. If 12 volts is present at the speed range shift switch but not at shift valve, the switch may be damaged, or the wiring between the switch and the shift valve may be faulty.
10. If 12 volts is not available at the speed range shift switch, check wiring from switch to keyswitch and alternator for continuity. Repair or replace faulty wiring or components.
Control Rod Length Adjustment
Propel Pump Control Linkage
(1) Clevis. (2) Propel link. (3) Clevis. (4) Locknut. (5) Rod. (6) Locknut. (7) Clevis. (8) Set dimension. (9) Bracket. (10) Bolt. (11) Bolt. (12) Rear control handle. (13) Bracket. (14) Front control handle.
The length of the control rod is set so that pump control handles (12) and (14) leave neutral at the same time when the operator moves the propel lever to FORWARD or REVERSE. This length is set at the factory, and should not be adjusted unless the propel pump control linkage is disassembled.
If the control rod is ever removed from the propel pump control linkage, perform the following steps to set rod length during reassembly.
1. Disconnect clevis (1) from propel link (2). Springs in the pump will move control handles (12) and (14) to the neutral position.
2. Loosen locknuts (4) and (6). Position clevises (3) and (7) so set dimension (8) is 284.73 ± .13 mm (11.210 ± .005 in.).
3. Tighten locknuts (4) and (6).
4. Loosen bolts (10) and (11). This will allow bracket (9) to move a little without moving pump control handle (12).
5. Install one end of the control rod to bracket (9). Install the other end of the control rod to bracket (13). Do not move pump control handles (12) and (14) from the neutral position during this step.
6. Tighten bolts (10) and (11).
7. Reconnect clevis (1) to propel link (2).
NOTE: If the control rod length is adjusted correctly, but both sections of the pump are not in neutral, there is a different problem. Components in the pump may be damaged, or the pump neutral setting may need to be adjusted.
NOTE: If engine will not start after performing this adjustment, see Neutral Start Switch Adjustment, in this module.
Pump Synchronization Adjustment
Propel Pump Control Linkage
(1) Bolt. (2) Adjusting nut. (3) Rear control handle. (4) Front control handle.
The propel pump control handles (3) and (4) must be synchronized to drive the drum and rear wheels equally during operation. Perform the following steps to check the pump synchronization, and adjust if needed.
1. Do the System Pressure Tests in this module. If the drum and wheel pressure readings differ by more than 1380 kPa (200 psi), the system must be adjusted as follows.
2. Loosen bolt (1).
3. If the drum pressure is higher than the rear wheel pressure, the propel linkage over control handle (4) must be raised. Turn nut (2) clockwise a few turns. This will raise the linkage a little.
4. If the drum pressure is lower than the rear wheel pressure, the propel linkage over control handle (4) must be lowered. Turn nut (2) counterclockwise a few turns. This will lower the linkage a little.
5. Tighten bolt (1).
6. Repeat the System Pressure Tests in this module to check the new setting.
7. Repeat steps 2 through 6, if necessary, until the drum pressure and wheel pressure are within 1380 kPa (200 psi) of each other.
NOTE: If the pump linkage can not be synchronized using this procedure, there may be a different problem in the system. Refer to the Troubleshooting and the other Tests and Adjustments to identify and solve the problem.
Propel Lever Adjustment
Propel Lever Control Linkage
(1) Back-up alarm. (2) Actuator arm. (3) Nut. (4) Detent for STOP position. (5) Propel lever. (6) Clevis. (7) Locknut. (8) Control cable (to propel pump).
The STOP position of the propel lever is defined by detent (4). When the propel lever is in the STOP position, both control handles (on propel pump) must be in neutral. Perform this procedure to check and adjust the propel lever.
1. Raise the entire machine on blocks so drum and rear wheels can rotate without moving machine.
2. Start engine and run at full throttle.
NOTE: If engine does not turn over when key is turned to START, neutral start switch could be misadjusted. See Neutral Start Switch Adjustment section of this module.
3. Release secondary/parking brake.
4. With propel lever in STOP position, drum and rear wheels should not rotate.
5. If drum and wheels do rotate, propel lever should be adjusted as follows.
6. Set propel lever so drum and wheels do not rotate.
7. Shut engine OFF without touching propel lever.
8. Disconnect clevis (6) from propel lever (5).
9. Move propel lever to STOP position.
10. Loosen locknut (7). Turn clevis (6) in or out as necessary to line clevis up with propel lever mounting hole. Retighten locknut (7).
11. Reconnect clevis (6) to propel lever (5).
NOTE: After completing this procedure, make sure the propel lever and both pump control handles are in the STOP or neutral position.
12. Adjust the setting of the back-up alarm. See Back-Up Alarm Adjustment section of this module.
Back-Up Alarm Adjustment
Propel Lever Control Linkage
(1) Back-up alarm. (2) Actuator arm. (3) Nut. (4) Detent for STOP position. (5) Propel lever. (6) Clevis. (7) Locknut. (8) Control cable (to propel pump).
1. Start engine and run at full throttle.
2. Release secondary/parking brake.
3. Nudge propel lever very slowly in the REVERSE direction.
4. Back-up alarm should sound as machine starts to move backwards.
5. Nudge propel lever back to the STOP position.
6. Back-up alarm should stop when machine stops.
7. If back-up alarm does not work as it should, the actuator mechanism should be adjusted as follows.
8. Nudge propel lever in the REVERSE direction so the machine just starts to move backwards.
9. Shut engine OFF without touching propel lever.
10. Loosen nut (3) on actuator arm (2), located underneath operator's console.
11. Adjust actuator arm (2) so it just closes the contacts in the back-up alarm (1). The switch will "click" as the contacts close.
12. Retighten nut (3).
NOTE: If actuator arm (2) is adjusted correctly, but back-up alarm does not work, the back-up alarm may be broken, or there may be a problem in the electrical system.
Neutral Start Switch Adjustment
Propel Pump Control Linkage
(1) Control cable (to propel lever). (2) Locknut. (3) Clevis. (4) Propel link. (5) Neutral start switch.
When the propel lever is in the STOP position, both pump control handles are in neutral. Neutral start switch must be closed to start the engine. Perform the following steps to adjust the control linkage to close the neutral start switch if necessary.
1. Move propel lever to the STOP position.
2. Disconnect clevis (3) from propel link (4).
3. Adjust propel link (4) so that neutral start switch, (5) is closed.
4. Loosen locknut (2). Turn clevis (3) in or out, as necessary, so clevis lines up with hole in propel link. Retighten locknut (2).
5. Reconnect clevis (3) to propel link (4).
NOTE: If propel link is set correctly, but neutral start switch does not work, the neutral start switch may be broken, or there may be a problem in the electrical system.