349F and 352F Excavators Hydraulic System Caterpillar

Specification

Introduction

This procedure will verify the pressures that the Automatic Travel Speed Control will shift between high speed travel and low speed travel.

Note: The engine speed and/or the machine configuration that is used during this test can affect the results of this test. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for the engine speed that was used for this test. Refer to Testing and Adjusting, "Operational Checks" for the machine configurations that were used for this test.

Note: The relief valve pressure settings must be set to the relief valve pressure specification before performing this operational check. Refer to Testing and Adjusting, "Specifications".

Required Tools

Illustration 1	g02571852
Tooling (A) 198-4240 Digital Pressure Indicator Gp

Illustration 2	g03261789

Machine Preparation

1. Position the machine on level ground.

2. Stop the engine.

3. Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "System Pressure - Release".
   Show/hide table

   Illustration 3	g02143242
   Pump compartment (1) Pressure tap (delivery pressure for drive pump) (2) Pressure tap (delivery pressure for idler pump) (3) Pressure tap (power shift pressure)

4. Connect a 41,368 kPa (6,000 psi) pressure sensor to pressure tap (1). Use this pressure sensor to monitor the pump pressure of the drive pump for right travel.

5. Connect a 41,368 kPa (6,000 psi) pressure sensor to pressure tap (2). Use this pressure sensor to monitor the pump pressure of the idler pump for left travel.
   Show/hide table

   Illustration 4	g03137183
   Sprocket (forward left travel) (D) Track Block (4) Sprocket

6. Place blocker pin (D) in sprocket (4) in order to block forward left travel. Refer to Illustration 4.

Test Procedure - HIGH Travel Speed (Rabbit Mode)

1. Start the engine.

2. Position the machine on level ground.

3. Place the hydraulic activation control lever in the UNLOCKED position.

4. Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).

5. Place the machine controls at the following settings: Engine speed dial "10" and AEC switch OFF.
   Show/hide table

   Illustration 5	g00297292

6. Raise the unblocked track off the ground. Refer to Illustration 5.

7. Place the travel speed control switch in HIGH position.

8. Move the travel lever of the raised track to full travel position and hold.

9. Slowly move the travel control lever of the blocked track to full FORWARD position and check the pressure at pressure tap (2) at which the travel speed changes from high to low. Refer to Table 1 for the high speed to low speed pressure specification.

10. Slowly return the travel control lever of the blocked track to the NEUTRAL position and check the pressure at pressure tap (2) at which the travel speed changes from low to high. Refer to Table 1 for the low speed to high speed pressure specification.

11. Return the travel control lever of the raised track to the NEUTRAL position.

12. Lower the raised track to the ground.

13. In order to test the automatic travel speed control on the right travel motor, place Track Block (D) in the sprocket for right travel. Use the pressure sensor at pressure tap (1) in order to monitor the idler pump pressure for the right travel motor. Repeat Steps 6 through 12 for the right travel motor.

Test Procedure - LOW Travel Speed (Tortoise Mode)

1. Start the engine.

2. Position the machine on level ground.

3. Place the hydraulic activation control lever in the UNLOCKED position.

4. Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).

5. Place the machine controls at the following settings: Engine speed dial "10" and AEC switch OFF.
   Show/hide table

   Illustration 6	g00297292

6. Raise the unblocked track off the ground. Refer to Illustration 5.

7. Place the travel speed control switch in LOW position.

8. Move the travel lever of the raised track to full travel position and hold.

9. Slowly move the travel control lever of the blocked track to full FORWARD position. The travel speed should remain at LOW speed.

10. Return the travel control lever of the blocked track to the NEUTRAL position.

11. Return the travel control lever of the raised track to the NEUTRAL position.

12. Lower the raised track to the ground.

13. In order to test the automatic travel speed control on the right travel motor, place Track Block (D) in the sprocket for right travel. Use the pressure sensor at pressure tap (1) in order to monitor the pump pressure for the right travel motor. Repeat Steps 6 through 12 for the right travel motor.