416D, 420D, 424D, 428D, 430D, 432D, 438D and 442D Backhoe Loaders Axles, Differential and Brakes Caterpillar

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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.

This section provides probable causes to known problems. Perform a visual inspection of the machine. Refer to Testing and Adjusting, "Visual Inspection".

Operational Checks

Operate the machine in each direction and in all speeds. Note the noises that are not normal and find the sources of the noises. If the machine is not operating correctly, refer to "Troubleshooting Problem List".

Troubleshooting Problem List

Problem List For The Service Brake

1. The service brakes do not operate.

2. The service brakes slip.

3. The service brakes are not applied evenly.

4. Too much force needed to push the brake pedal.

Problem List For The Parking Brake

1. The parking brake does not hold the machine stationary.

2. The parking brake does not engage when the parking brake control lever is actuated.

3. The engine is running and the parking brake is in the ENGAGED position. However, the parking brake alarm does not sound when the transmission is put into the FORWARD direction or into the REVERSE direction.

Problem List For The Axles and Differential

1. There is constant noise in the differential.

2. Noise occurs in the differential at different intervals.

3. Noise only occurs during turns.

4. Lubricant is leaking.

5. The drive wheels do not turn but the universal joint turns.

Problem List For All Wheel Steer

Note: Refer to Testing and Adjusting, RENR3581, "Hydraulic and Steering Systems" and Testing and Adjusting, RENR3584, "Hydraulic and Steering Systems" for further information.

Note: Refer to Systems Operation, RENR3580, "Hydraulic and Steering Systems" or Systems Operation, RENR3583, "Hydraulic and Steering Systems"for information on the systems operation of the All Wheel Steer.

1. In the Two-Wheel Steer mode, the rear axle drifts excessively. Maximum allowable drift is 2.0 mm (0.08 inch) within 60 minutes.

2. The machine does not travel in a straight line and the rear axle position gauge is centered.

Troubleshooting Probable Causes

Probable Causes To Problems Of The Service Brake

Problem 1

The service brakes do not operate.

Probable causes

1. The brake group within the axle housing is damaged.

2. The lines to the service brakes are obstructed.

Problem 2

The service brakes slip.

Probable causes

1. Incorrect additives added to the oil in the axle.

2. The brake discs in the axle housing are worn.

Problem 3

The service brakes are not applied evenly.

Probable causes

1. The brake discs and associated components in the axle housing are excessively worn.

2. The service brake valve is sticking because of contaminated oil.

3. The service brake valve is not delivering the correct amount of pressure.

Problem 4

Too much force needed to push the brake pedal.

Probable causes

1. The brake pedals and/or brake pedal linkages are damaged.

2. The service brake valve is sticking because of contaminated oil.

Probable Causes To The Problems Of The Parking Brake

Problem 1

The parking brake does not hold the machine stationary.

Probable causes

1. The parking brake is out of adjustment.

2. The brake linings are worn.

3. There is grease or oil on the brake disc and/or on the brake lining.

Problem 2

The parking brake does not engage when the parking brake control lever is actuated.

Probable causes

1. The parking brake cable is disconnected.

2. The parking brake cable has stretched until the cable will not actuate the parking brake.

3. The parking brake is out of adjustment.

Problem 3

The engine is running and the parking brake is in the ENGAGED position. However, the parking brake alarm does not sound when the transmission is put into the FORWARD direction or into the REVERSE direction.

Probable causes

1. The parking brake alarm has failed.

2. There is a problem in the electrical circuit.

Probable Causes to the problems of the Axles and the Differential

Problem 1

There is constant noise in the differential.

Probable causes

1. The level of lubricant is incorrectly high or low.

2. The wrong type of lubricant is being used.

3. Wheel bearings are damaged or improperly adjusted.

4. The ring gear and the pinion do not have correct tooth contact.

5. The ring gear and the pinion are damaged or worn.

6. There is too much pinion to gear backlash or too little pinion to gear backlash.

7. Pinion bearings are loose or worn.

8. Side bearings are loose or worn.

Problem 2

Noise occurs in the differential at different intervals.

Probable causes

1. Ring gear does not run evenly because the bolts on the ring gear are not tight or the ring gear is warped.

2. Differential bearings are loose or broken.

Problem 3

Noise only occurs during turns.

Probable causes

1. Differential pinion gears are too tight.

2. Side gears are too tight in the differential case.

3. Differential pinion gears or side gears are faulty.

4. Thrust washers are damaged or worn.

5. There is too much backlash between the side gears and the pinion gears.

Problem 4

Lubricant is leaking.

Probable causes

1. Loss of lubricant through the axle shafts can be caused by any of the following conditions:

   1. Lubricant is above the proper level.

   2. The wrong type of lubricant is being used.

   3. The oil seal on the axle shaft is worn or installed incorrectly.

2. Loss of lubricant at the pinion shaft can be caused by the following conditions:

   1. Lubricant is above the proper level.

   2. The wrong type of lubricant is being used.

   3. An oil seal on the pinion shaft is worn or installed incorrectly.

Problem 5

The drive wheels do not turn but the universal joint turns.

Probable causes

1. An axle shaft is broken.

2. Ring gear teeth are damaged.

3. The side gear or the differential pinion is broken.

Probable Causes of All Wheel Steer Problems

Problem 1

In the Two-Wheel Steer mode, the rear axle drifts excessively. Maximum allowable drift is 2.0 mm (0.08 inch) within 60 minutes.

Probable cause

1. The seals in the cylinders are leaking.

2. The lock valve is leaking.

Problem 2

The machine does not travel in a straight line and the rear axle position gauge is centered.

Probable causes

1. The sensor for the rear axle position is out of adjustment.

2. The selector switch for the All Wheel Steer is malfunctioning.