267, 277 and 287 Multi Terrain Loaders Machine Systems Caterpillar

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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, perform the procedure that follows before testing and adjusting the power train.

Before any tests are performed, prepare the machine. Refer to Testing and Adjusting, "Machine Preparation". Before any tests are performed, visually inspect the complete hydraulic system for oil leaks and damaged parts. Refer to Testing and Adjusting, "Visual Inspection".

The tests for the hydraulic system should be done in the following order. In order for the hydrostatic system to function correctly, each component in the system must be set to the correct specifications. Some components must be set prior to the testing of other components. A component that is not set correctly will have an impact on other components in the system.

It is not advisable to bypass preceding tests. Do not perform a test before the tests that precede that test have been done. Table 1 lists the equipment that is needed to perform testing on the hydrostatic system. Equivalent tooling may be substituted.

Clearly mark all of the hoses and the corresponding pressure gauges, when the hoses are installed. The hoses and the pressure gauges will be used multiple times in the testing and adjusting procedures.

Throughout the entire testing procedure, MB pressure refers to the hydraulic oil pressure in the forward hydrostatic loop. MA pressure refers to the hydraulic oil pressure in the reverse hydrostatic loop.

Note: The oil in the hydraulic system must be at an operating temperature of 50° ± 10°C (122° ± 18°F). In order to increase the oil temperature, start the engine and operate all the cylinders for at least five cycles. Also, drive the machine forward and drive the machine rearward for a few minutes.

Baseline for the Hydrostatic System

The test must be performed in order to establish a starting point for the hydrostatic system. After this test has been completed a baseline for the remaining tests will have been established.

Clearly mark all of the hoses and the corresponding pressure gauges as you install the hoses.

1. Use cribbing to elevate the machine. The tracks must not touch the ground.

2. Release the hydraulic system pressure. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release" for the correct procedure.

3. Raise the cab. Refer to Operation and Maintenance Manual, "Cab Support Operation" for the correct procedure.

4. Install a 8T-0855 Pressure Gauge to one end of a 1U-5755 Hose .

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Illustration 1	g00788958
(1) Charge pressure tap

5. Install an 8T-0855 Pressure Gauge to the charge pressure tap (1) with a 1U-5755 Hose .

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Illustration 2	g00804364
(2) Speed sensing pressure tap

6. Install an 8T-0855 Pressure Gauge to the speed sensing pressure tap (2) with a 1U-5755 Hose .

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Illustration 3	g00804369
Ports (3) for the pump case.

7. Install the 6V-3966 Valved Nipple to the port for the pump case (3) with the 5P-2937 Adapter and with the 3J-7354 O-Ring Seal .

8. Install a 6V-3121 Multitach, or install a 9U-7400 Multitach Tool Group in order to measure engine rpm. Use reflective tape on the pulley for the engine crankcase to measure the rpm.

9. Install either a 6V-3121 Multitach or a 9U-7400 Multitach Tool Group in order to measure fan rpm. Use reflective tape on the fan blade to measure the rpm.

10. Lower the cab. Route the test hoses so that the cab does not rest on any of the hoses. Route the test lines in order to avoid pinching the hydraulic lines when the cab is lowered.

11. Start the engine and run the engine at low idle.

    If the engine speed for low idle is incorrect, perform the following adjustments to the cable assembly of the governor control:

    • Set the throttle to the HIGH IDLE position.

    • Install the cable assembly to the engine so the cable nuts can be positioned and tightened in order to set the throttle's bracket. The bracket must make contact with the high idle stop.

    • Move the throttle to the LOW IDLE position.

    • Adjust the 6V-7357 Bolt until the low idle stop remains in slight contact with the bracket.

    • Tighten the 5C-2890 Nut in order to lock the bolt in place.

    Note: Low idle and high idle have been preset at the factory. The setting of the low idle and the high idle on these engines should not be adjusted. Adjusting the setting can void the warranties on the fuel injection pump and the engine. Adjusting the setting can invalidate the standards for emissions. Adjustment of the low idle and the high idle should be made only by trained personnel. The low idle and high idle for most engine applications is given in the Systems Operation, "Engine Design". Some engine applications may have a different low idle and high idle.

    Note: Verify the engine rpm for the low idle and the high idle by referring to the Technical Marketing Information (TMI) or to the Fuel Setting and Related Information Fiche.

12. Record the following items: the charge pressure, the speed sensing pressure, the pressures for the pump case on the piston pump, the engine RPM and the fan RPM.

13. Increase the engine speed to high idle.

    If the engine speed for high idle is incorrect, perform the following checks:

    • Set the throttle to the HIGH IDLE position.

    • Install the cable assembly to the engine so the cable nuts can be positioned and tightened in order to set the throttle's bracket. The bracket must make contact with the high idle stop.

    • Move the throttle to the LOW IDLE position.

    • Adjust the 6V-7357 Bolt until the low idle stop remains in slight contact with the bracket.

    • Tighten the 5C-2890 Nut in order to lock the bolt in place.

    Note: Low idle and high idle have been preset at the factory. The setting of the low idle and the high idle on these engines should not be adjusted. Adjusting the setting can void the warranties on the fuel injection pump and the engine. Adjusting the setting can invalidate the standards for emissions. Adjustment of the low idle and the high idle should be made only by trained personnel. The low idle and high idle for most engine applications is given in the Systems Operation, "Engine Design". Some engine applications may have a different low idle and high idle.

    Note: Verify the engine rpm for the low idle and the high idle by referring to the Technical Marketing Information (TMI) or to the Fuel Setting and Related Information Fiche.

14. Record the following items: the charge pressure, the speed sensing pressure, the pressures for the pump case on the piston pump, the engine speed and the fan speed.

If the charge pressure is too low or too high at high idle, perform the following checks.

• Check the gear pump for wear by checking the fan speed.

• The possibility exists of a large internal leak in the following components: brakes, piston pump, piston motors and pilot operated hydraulic controls. Refer to Table 3 in order to troubleshoot these components.

• Replace the charge relief valve and recheck the pressure.

• The fan motor may have failed.

• Check for a restriction in the filter.

If the charge pressure is too low at low idle, perform the following checks.

• The possibility exists of a large internal leak in the following components: brakes, piston pump, piston motors and pilot valves. Refer to Table 3 in order to troubleshoot these components.

If the case pressure of the piston pump is high, perform the following checks.

• Check for a restriction in the hydrostatic lines.

• Check the hydraulic oil temperature. Make sure that the operating temperature of the hydraulic oil is correct. Check the viscosity of the hydraulic oil.

• There may be an internal leak.

• The possibility exists of a worn piston pump.

If the pressure for the pump case for the piston pump is low, perform the following checks.

• The lip seal for the shaft of the piston pump is blown. Check for a hydraulic oil leak.

If the speed sensing pressure is low, perform the following adjustment.

• Turn the adjustment screw on the speed sensing valve counterclockwise.

If the speed sensing pressure is high at low idle, perform the following adjustment.

• Turn the adjustment screw on the speed sensing valve clockwise.

Note: Do not disconnect the lines or the gauges if adjustments need to be performed. The gauges will be used in order to check the pressures for the required tests and adjustments. Leave the 6V-3121 Multitach or the 9U-7400 Multitach Tool Group connected in order to measure the engine rpm for the tests that follow.

Start To Move Test

Perform the start to move test in order to make sure that the piston pump is synchronized. If the pump is not synchronized, the machine could drift or the machine could move with the pilot operated hydraulic control ( hydrostatic) in the NEUTRAL position. If the pump is not synchronized, the wheels on one side of the machine could start to move before the wheels on the other side of the machine start to move.

Note: If the left track and the right track start to move at the same time, this test is not required.

1. Use cribbing to elevate the machine. The tracks must not touch the ground.

2. Raise the cab. Refer to Operation and Maintenance Manual, "Cab Support Operation" for the proper procedure.

   Note: Perform the test on rotating group 2 of the piston pump only. Rotating group 2 powers the piston motor which is on the right side of the machine. Rotating group 2 is farthest from the engine.

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Illustration 4	g00804469
(1) Neutral adjusting bolt for rotating group 2

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Illustration 5	g00804475
(2) MA Port for rotating group 2 (3) MA Port for rotating group 1

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Illustration 6	g00905470
(4) MB Port for rotating group 1 (5) MB Port for rotating group 2

3. Install one 8T-0860 Pressure Gauge to the MA port and to the MB port on rotating group 2. Use the 1U-5755 Hoses to connect the gauges to the ports.

4. Place the two gauges in an easily visible position.

5. Lower the cab. Route the test hoses so that the cab does not rest on any of the hoses.

6. Fasten the seat belt and lower the armrest.

7. Start the engine and run the engine at low idle.

8. Raise the cab.

9. Loosen the locknut for the neutral adjusting bolt. Do not use an impact socket.

10. Turn neutral adjusting screw (1) clockwise. Mark the location of the neutral adjusting bolt when the MB pressure begins to increase.

11. Turn neutral adjusting screw (1) counterclockwise. Mark the location of the neutral adjusting bolt when the MA pressure begins to increase.

12. Turn the neutral adjusting screw midway between the two marks.

13. Hold the neutral adjusting screw in position as you tighten the locknut to a torque of 44 ± 2 N·m (32 ± 1 lb ft).

14. Lower the cab.

15. Sit in the operator's seat and fasten the seat belt. Lower the armrest.

Note: In the next step, the tracks will rotate. Make sure that all hoses are out of the way of the rotating tracks.

16. Move the pilot operated hydraulic control ( hydrostatic) slowly forward. Check that the left track and the right track start to move at the same time.

17. If the tracks do not start to move at the same time, then repeat this adjustment procedure for rotating group 1.

Maximum Runout

The test is used to determine if the engine and the machine speeds are correct for the maximum travel speed.

1. The hose assemblies and gauges for charge pressure and for speed sensing pressure should still be in place. If the units are not in place, reinstall the units.

2. The hose assemblies for the MB port for rotating group 2 should still be in place. Connect another hose assembly to the MB port for rotating group 1.

3. The machine should still be blocked up. The tracks must not touch the ground.

4. The 6V-3121 Multitach or the 9U-7400 Multitach Tool Group should still be installed on the machine. If a unit is not installed, reinstall a multitach.

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Illustration 7	g00804496
The illustration shows the correct placement of the reflective tape.

5. Apply four pieces of reflective tape to each sprocket at 90 degree intervals. Use a 1U-6602 Phototach to record the rpm of the wheels.

6. Start the machine and run the machine at high idle. Push in the FORWARD direction on the pilot operated hydraulic control ( hydrostatic). If the machine is equipped with two speed capability, run the machine in both the rabbit mode and the normal mode. Record the rpm of the motor on each side of the machine and divide that number by four.

7. Record the MB pressures, the speed sensing pressures, the charge pressure and the wheel rpm.
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   Table 5

   MAXIMUM RUNOUT
   Test	Specification
   Engine Speed	2820 ± 50 RPM for the 267 2900 ± 50 RPM for the 277
   Speed Sensing Pressure	2500 ± 100 kPa (365 ± 15 psi)
   Charge Pressure	3300 ± 200 kPa (480 ± 30 psi)
   MB Pressure Pump 1	6000 ± 500 kPa (800 ± 85 psi)
   MB Pressure Pump 2	6000 ± 500 kPa (800 ± 85 psi)
   Sprocket Speed	150 ± 3 RPM for the 267 155 ± 3 RPM for the 277 (1)

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   ( 1 )

   The sprocket speeds must be within 2 RPM of each other.

Perform the following check if the speed sensing pressure is not to the correct specification:

• The piston pump is not providing full power.

• The speed sensing valve may be misadjusted.

Perform the following check if the MB pressure and the MA pressure is high for the FORWARD direction and the REVERSE direction.

• The brake may not be disengaged.

Maximum Displacement Stop Test

This test will determine if each displacement stop is adjusted correctly in each rotating group. The two displacement stops adjust the maximum stroke of the swashplate in each of the rotating groups in the forward direction.

Note: Before you adjust the displacement stops, the right side track and the left side track must begin to move at the same time. Refer to the "Start to Move Test".

Note: If the machine drifts to the same side in both forward and reverse, check the track tension on both sides of the machine before you proceed with the test.

1. Perform the test for maximum runout. Refer to the Testing and Adjusting, "Maximum Runout".

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Illustration 8	g00905473
Turn the adjustment screw (A) clockwise when the machine drifts to the left. Turn the rear adjustment screw (B) clockwise when the machine drifts to the right.

2. If the sprocket speed for the right side track is greater than the specification, you must turn the adjustment screw (A) by 1/8 of a turn clockwise.

   If the sprocket speed for the left side track is greater than the specification, you must turn the adjustment screw (B) by 1/8 of a turn clockwise.

   Note: After every adjustment to an adjustment screw, repeat the drift test until the machine drift is acceptable.

3. After you finish adjusting an adjustment screw, tighten the locknut to a torque of 22 N·m (16 lb ft). Cover the maximum displacement adjustment screws with 6E-5060 Caps .

Stall Test

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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, perform the procedure that follows before testing and adjusting the power train.

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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

The test can be used in order to identify low power problems with the engine. The test is also used to identify the crossover relief valves that may be malfunctioning.

1. Raise the cab. Refer to Operations and Maintenance Manual, "Cab Support Operation" for the correct procedure.

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Illustration 9	g00804524
(1) Electrical connection (2) Brake solenoid

2. Position the machine against an object that will prevent the machine from moving. It is possible to drive through the brakes. Disconnect the electrical connection (1) for the brake solenoid (2) .

3. The 6V-3121 Multitach or the 9U-7400 Multitach Tool Group should still be installed on the machine. If a unit is not installed on the machine, reinstall a multitach.

4. The two 1U-5755 Hose Assemblies should still be connected to the MB pressure ports. If the hoses are not still connected, reconnect the hoses.

5. Lower the cab.

6. Sit in the operator's seat and fasten the seat belt. Lower the armrest.

7. Start the engine and run the engine at low idle.

8. Slowly increase the engine speed to high idle.

9. Push the pilot operated hydraulic control ( hydrostatic) to the FORWARD position until the engine stalls.

Note: The tracks should not spin. If the tracks spin, refer to the "Brake Test".

10. Record the engine rpm and record the MB pressures for the two drive loops.

If the engine rpm is low, perform the following check:

• The piston pump may have an internal leak, or the piston motor may have an internal leak.

• The engine power may be low.

• The speed sensing valve may be set too high.

Perform the following check if the engine rpm is high for the stall of the hydrostatic system:

• The speed sensing valve may be set too low.

If the MA pressure is low and the engine lug is high, perform the following checks:

• The crossover relief valve is set incorrectly. Switch the two crossover relief valves. If the problem is not corrected then replace the piston pump.

Double Stall Test

The test will determine if engine performance is low.

Note: The 6V-3121 Multitach or the 9U-7400 Multitach Tool Group should still be installed on the machine. If the unit is not installed, reinstall the unit.

1. The two 1U-5755 Hose Assemblies should still be connected to the MB pressure ports. If the hoses are not still connected, reconnect the hoses. The brake solenoid should still be disconnected. If the brake solenoid is not disconnected, disconnect the solenoid.

2. Start the engine.

3. Increase the engine speed to high idle.

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Illustration 10	g00698449

Note: Do not stall the machine for more than 15 seconds. Damage to the machine could result.

4. Push the pilot operated hydraulic control ( hydrostatic) in the FORWARD direction.

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Illustration 11	g00790274

5. At the same time, push the pilot operated hydraulic control ( work tool) to the TILT BACK position.

6. Record the MB pressures and the engine rpm.

If the engine rpm is not to the correct specification, perform the following checks:

• The engine power is low. Check the throttle, injectors, and fuel pressure.

• Check for a parasitic load.

• Check the speed sensing valve. Adjust the speed sensing valve if the setting is not set to specifications.

• Check the main relief valve. Adjust the main relief valve if the setting is not set to specifications.

Perform the following check if the engine lug is satisfactory for the stall of the hydrostatic system, but the engine lug is low for the stall of the hydraulic system:

• The main relief valve may be set too low.

• There may be an internal leak in the hydraulic system.

Perform the following check if the engine lug is satisfactory for the stall of the hydrostatic system, but the engine lug is high for the stall of the hydraulic system:

• The engine may have low power.

• The main relief valve may be set too high.

Perform the following check if the engine lug is satisfactory for the stall of the hydraulic system, but the engine lug is high for the stall of the hydrostatic system.

• The piston motor may have an internal leak.

• The piston pump may have an internal leak.

• The crossover relief valve may be set too low or the crossover relief valve may be damaged.

• The speed sensing valve may be set too high.

Brake Test

This test will determine if the brakes are functioning correctly. This test will also check the piston motor.

Note: It is possible to drive through the brakes on the 267 and the 277 Multi Terrain Loader. Position the machine against an object that will prevent the machine from moving.

1. The brake solenoid should still be disconnected. If the brake solenoid is not disconnected, disconnect the solenoid.

2. Raise the cab. Refer to Operation and Maintenance Manual, "Cab Support Operation".

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Illustration 12	g00856151

3. Install a 8T-8902 Tee and a 6V-3965 Valved Nipple Assembly in the hydraulic line that runs from the brake solenoid to the piston motors.

4. Install a 8T-0855 Pressure Gauge to the valved nipple with a 1U-5755 Hose .

5. Lower the cab. Make sure that the hydraulic line is not pinched.

6. Sit in the operator's seat and fasten the seat belt. Lower the armrest.

7. Start the machine. The pressure gauge should read 0. If the gauge does not read 0, inspect the brake solenoid and the voltage for the brake solenoid.

8. Stop the machine. Raise the cab and reconnect the brake solenoid.

9. Lower the cab. Sit in the operator's seat and fasten the seat belt. Lower the armrest and start the machine. Set the governor at low idle.

10. Disengage the parking brake by pressing the parking brake switch. The pressure on the gauge should be 3200 ± 200 kPa (465 ± 30 psi).

11. If the pressure is not correct, inspect the following items: the brake solenoid, the voltage for the brake solenoid and the brake seal inside the piston motor.

12. If the brake solenoid is not functioning correctly, replace the solenoid.

13. When the test is completed, raise the cab and disconnect all gauges and hoses. Lower the cab and bolt the cab in place. Refer to Operation and Maintenance Manual, "Cab Support Operation".