992K Wheel Loader and 854K Wheel Dozer Braking System Caterpillar

This section provides probable causes to a known problem. Since there may be several probable causes, specific inspections or specific instrument tests may be recommended. These inspections and tests will help to identify the cause that is most probable.

Problem 1

The front service brakes do not operate.

Probable Causes

• The front accumulator is damaged or faulty.

• A seal in the internal brake line or in the brake group is damaged or worn.

• The brake pump failed or the brake pump is damaged.

• The brake group is damaged within the interfaces between the spindles and the axle housings.

Problem 2

The rear service brakes do not operate.

Probable causes

• The rear accumulator is damaged or faulty.

• A seal in the internal brake line or in the brake group is damaged or worn.

• The brake pump failed or the brake pump is damaged.

• The brake group is damaged within the interfaces between the spindles and the axle housings.

Problem 3

The service brakes slip.

Probable causes

• A seal in the internal brake line or in the brake group is worn or damaged.

• The brake discs in the brake group are worn.

Problem 4

The service brake application is uneven.

Probable causes

• There is air in the hydraulic oil for the brake group.

• There is excessive wear on one or more brake discs and on the associated components in the brake group.

• The brake valve is sticking or damaged.

Problem 5

Too much force is needed in order to depress the brake pedals.

Probable causes

• The brake pedals and the pedal linkages are damaged.

• The brake valve is sticking or damaged.

• Pedal movement to the cab floor is obstructed.

Problem 6

The warning for low brake oil pressure will not turn off.

Probable causes

• The hydraulic oil temperature is too high.

• The brake pump is worn or damaged.

Problem 7

The parking brake does not hold the machine in place.

Probable causes

• The parking brake must be adjusted.

• The brake linings are worn.

• There is grease or oil on the brake drum and on the brake lining.