994K Wheel Loader Machine Systems Caterpillar

Brake System Air - Purge

Usage:

994K MM9

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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. Keep the hydraulic tank full during the procedure.

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Illustration 1	g03884857
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 wheel chocks 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 2	g03883667
View of the dash panel (2) Parking brake control switch

Place parking brake control switch (2) in the ON position in order to activate the parking brake.
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Illustration 3 g03883675

View of the parking brake assembly (parts removed for clarity)
(3) Air purge screws (two)
Connect a hose to each air purge screw (3) on both sides of the parking brake assembly. Put the other end of the hoses in a clear container.
Slowly open each air purge screw (3), one at a time, 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.