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

Brake System Air - Purge

Usage:

992K 880

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NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat^® products. Dispose of all fluids according to local regulations and mandates.

There must be no air in the hydraulic oil. Air in the system can prevent the complete application of the brakes.

Move the machine to a hard, level surface that is dry and free of debris.
Install the steering frame lock.
Set the parking brake.
Check the oil level in the hydraulic tank for the steering system and for the braking system. Keep the hydraulic tank full during the procedure.
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Illustration 1 g01440199

Left side view

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Illustration 2 g00110073

Typical air purge screw for the service brakes
(1) Air purge screw
Connect a hose to air purge screw (1). Put the other end of the hose in a clear container.
Start the engine and run the engine at low idle.
Open air purge screw (1) so that oil can flow through the hose. Depress the brake pedal until the flow of oil from the hose is free of air bubbles.
Close the air purge screw. Repeat this procedure for each service brake, but purge only one service brake at a time.
Fill the hydraulic oil tank to the correct level.
If the service brakes seem spongy during operation, perform the procedure again.

Place wood blocks in front of the tires and behind the tires.
Start the engine and allow the oil pressure to reach the cutout pressure. Stop the engine.
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Illustration 3 g02701896

Parking brake control knob
Push in the parking brake control knob.
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Illustration 4 g01440203

Left side view

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Illustration 5 g02702497

Air purge screw for the parking brake
(2) Air purge screw
Connect a hose to air purge screw (2) on the side of the parking brake housing. Put the other end of the hose in a clear container.
Slowly open air purge screw (2) so that oil can flow through the hose. Allow the oil to flow until there are no air bubbles in the oil. Close the air purge screw.