BRACKET AS. 2804030 - Caterpillar

Check For Leakage
1. Push brake pedal down and keep it in that position.2. Put soap suds on the connections of the air lines at the master cylinders and check for air leakage.3. Release the pedal.4. Put soap suds on the exhaust openings of the control valve for the brakes.5. When the pedal is pushed down, leakage must not be more than a 25.4 mm (1 in.) soap bubble in one minute.6. Repair any air leaks that are found.Control Valve For Service Brakes
The foot service brakes can give some problems with control valves that stick (will not open or close when needed). It is possible that the cause of this is a worn seat in the inlet check valve for the air reservoir. If this is the cause, replacement of only the control valve will not correct the problem.The sequence of failure caused by a worn seat in the inlet check valve is as follows: 1. The inlet check valve with a worn seat causes loss of air pressure.2. Loss of air pressure causes the air compressor to work more, and increases piston ring wear. Ring wear permits the compressor crankcase oil to enter the air system.3. Too much oil in the air system washes the white lubrication out of the control valve. This can cause the control valve to stick.4. Too much oil in the air system will also put carbon deposits in the air compressor governor. Carbon in the air compressor governor can cause air pressure to build up higher than necessary. This also increases piston ring wear in the compressor.Failure of front and/or rear service brakes to release is an indication of a defect in the brake control valves. Remove and disassemble the brake control valves. Check for the white lubricant which should be there. If the white lubricant is gone (it will be oily if the white lubricant is gone) check the air compressor, and the inlet check valve before you install a new brake control valve.Letting Air From Brakes (Bleeding The Brakes) (Machines Before 51S544 And 78W311)
Valve That Lets The Air Out (Bleed Valve)Let the air out of system for the wheel brakes which is activated by the master cylinder.1. Check the fluid level in the reservoir. The primary level must be 12.7 mm (.5 in.) from the top of the reservoir. To keep air out of the master cylinder, fluid must always be seen in the reservoir while air is being let out of the system. When filling an empty system, loosen the caps on the master cylinders until fluid comes out, then tighten the caps.2. Fasten a 6.3 mm (.25 in.) I.D. (inside dimension) hose to the valve that lets the air out. Put the loose end of the hose into a jar that has enough fluid in it so that the end of the hose is under the surface of the fluid.3. Push