120M, 12M, 140M and 160M Motor Graders Machine Systems Caterpillar

Illustration 1	g02148890

Introduction

This procedure provides information on the testing and the adjusting of the air compressor governor.

Required Tooling

Illustration 2	g01623868

Machine Preparation

1. Move the machine to a smooth, horizontal location. Move the machine away from other operating machines and away from personnel and lower all implements to the ground. Place the transmission direction control lever in the NEUTRAL position. Stop the engine and put chocks in front of the wheels and behind the wheels.

2. Open drain valve (5) in order to release the air pressure from air tank (4) .

3. Remove plug (3) from air tank (4) and install Tooling (F) and Tooling (G) .

4. Connect Tooling (B) to Tooling (F) .

Test Procedure

1. Start the engine. Allow the air pressure to increase to the cut out pressure. The cut out pressure should be 1000 ± 34 kPa (145 ± 5 psi). Record the pressure.

2. Slowly open drain valve (5) . Continue to release air pressure from air tank (4) until the air compressor turns on. The cut in pressure should be 793 kPa (115 psi). Record the pressure.

3. If necessary, make the following adjustments to air compressor governor (1) :

   1. Remove cover (2) .

   2. Loosen the locknut on the adjustment screw.

   3. Turn the adjustment screw counterclockwise in order to raise the cut out pressure.

   4. Turn the adjustment screw clockwise in order to lower the cut out pressure.

4. If the adjustment screw does not change the cut out pressure, the unloading valves in the air compressor are operating incorrectly.

5. If the difference between the cut in pressure and the cut out pressure is incorrect, the air compressor governor is operating incorrectly.

6. Stop the engine.

7. Open drain valve (5) in order to remove the air pressure from air tank (4) .

8. Remove the test equipment and install plug (3) into the original position.

9. Close drain valve (5) .