574B Forwarder Power Train Hydrostatic Drive System Performance - Test Caterpillar

Description of Test

Do not perform the following test until you have performed the procedures in Systems Operation, Testing and Adjusting, "Power Train Charge System Pressure - Test".

The following procedure is used in order to determine whether the power train pump or the power train motor has excessive internal leakage.

Preparation for Testing

1. Tilt the cab.

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Illustration 1	g00918320
Power Train Pump (Y) Port (forward direction). (Z) Port (reverse direction).

2. Remove the plugs from ports (Y) and (Z) .

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Illustration 2	g00918342
(A) 6V-3965 Fitting. (B) 3J-1907 O-Ring Seal. (C) 8T-7861 Connector. (D) 6V-6560 O-Ring Seal .

3. Install the components that are shown in Illustration 2 onto ports (Y) and (Z) of the power train pump. Connect a 0 to 2000 kPa (0 to 290 psi) pressure gauge to each pressure tap.

   Note: The pressure reading at ports (Y) and (Z) is stroking pressure. The pressure reading at port (Y) measures the stroking pressure in the forward direction. The pressure reading at port (Z) measures the stroking pressure in the reverse direction.

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Illustration 3	g00918348
(1) Wire connector. (2) Parking brake valve.

4. Disconnect wire connector (1) from parking brake valve (2) .

   This prevents the parking brake from disengaging.

5. Tilt down the cab.

6. Unlock the current settings of the power train pump in your IQAN system. See "Unlock Current Settings".

Unlock Current Settings

The current settings for the options in the "Maintenance" menu are locked at the factory. A PC that is equipped with IQANtalk software must be used to unlock these current settings for adjustment.

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Illustration 4	g00915930
IQANtalk Connection

1. Connect a serial cable between your PC and the IQAN system of your machine. The IQANtalk connection is a 9-pin connector that is located behind the rear access panel in the cab.

2. Turn the engine start switch to the ON position.

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Illustration 5	g00915955

3. Select "Get" from "System" menu (1) or select icon (2) in order to receive the current parameters from your IQAN system.

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Illustration 6	g00915956

4. Select "Hydrostat" from "Function" menu (3). The following window will appear.

5. Change the value for the "Trim transm." (4) to a value of "1".

6. Select "Send F2" (5) or press "F2" in order to send the current parameters for the "Hydrostat" option. This will allow the "XMSN pump" option and the "XMSN motor" in the "Maintenance" menu to be adjusted on your IQAN display.

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Illustration 7	g00916000
IQAN Terminal (Main Menu) (6) Menu key.

7. At the main menu of the IQAN display, press menu key (6) and then press the right arrow key. The following screen will appear.

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Illustration 8	g00916015

8. Press the function key beside the "Maintenance" option. The following window will appear.

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Illustration 9	g00916018

9. Press the function key beside the "XMSN pump" option. The following window will appear.

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Illustration 10	g00917018
IQAN Screen (Current settings to the proportional solenoids on the power train pump)

10. Set the minimum current of the drive loop to 170 mA and the maximum current of the drive loop to 360 mA. If the minimum current is set higher than 170 mA, the drive loop pressure will increase too fast for the test procedure.

Test

You must monitor the high pressure circuit of the drive loop in the forward and reverse direction for this test.

1. Start the engine. Increase the engine speed to 1500 rpm with the engine speed potentiometer. Turn the machine speed potentiometer to 0.

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Illustration 11	g00916000
IQAN Terminal (Main Menu) (6) Menu key.

2. At the main menu of the IQAN display, press the menu key (6) and then press the right arrow key. The following screen will appear.

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Illustration 12	g00918446

3. Press the function key beside the "Measure" option. The following window will appear.

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Illustration 13	g00918447

4. Press the function key beside the "Voltage in" option.

5. Forward
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   Illustration 14	g00918444

   1. Move the direction selector switch to the FORWARD position. Place the machine in HIGH speed.

   2. Depress the accelerator pedal halfway.
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   Illustration 15	g00918320
   Power Train Pump (Y) Port (forward direction). (Z) Port (reverse direction).

   3. Very slowly turn the machine speed potentiometer until the pressure reading of "HP FWD" reaches 50 Bar. Record the stroking pressure at port (Y) .

   4. Continue to turn the machine speed potentiometer until the pressure reading of "HP FWD" reaches 350 Bar. Record the stroking pressure at port (Y) .

   5. Release the accelerator pedal.

6. Reverse:
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   Illustration 16	g00918444

   1. Move the direction selector switch to the REVERSE position. Place the machine in HIGH speed.

   2. Depress the accelerator pedal halfway.
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   Illustration 17	g00918320
   Power Train Pump (Y) Port (forward direction). (Z) Port (reverse direction).

   3. Very slowly turn the machine speed potentiometer until the pressure reading of "HP REV" reaches 50 Bar. Record the stroking pressure at port (Z) .

   4. Continue to turn the machine speed potentiometer until the pressure reading of "HP REV" reaches 350 Bar. Record the stroking pressure at port (Z) .

   5. Release the accelerator pedal.

7. Stop the engine.

   Note: The difference between the stroking pressures for the forward and reverse directions should not be more than 120 kPa (17 psi).

8. If the difference between the stroking pressures for the forward and reverse directions are out-of-range, perform Step 9 through Step 11.

9. Tilt the cab.

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Illustration 18	g00918483
Location of Power Train Pump (underneath cab) (7) Oil line (drive loop) (forward). (8) Oil line (drive loop) (reverse).

10. Disconnect oil lines (7) and (8). Use covers (E) and rectangular seals (F) to block ports "P2(S)" and "S(P2)" on the power train pump.

    Note: When high pressure oil flows from the "P2(S)" port, the machine travels forward. When high pressure oil flows from the "S(P2)" port, the machine travels backward.

11. Tilt down the cab and repeat Step 5 and Step 6.

    Note: The difference between the stroking pressures for the forward and reverse directions should not be more than 60 kPa (9 psi). If the difference between the two pressure readings is within the correct range, the source of the leakage is most likely from the power train motor.