BEARING- 8N7925 - Caterpillar

Important! Please Read
When working on or around air brake systems and components, the following precautions should be observed:1. Always block vehicle wheels. Stop engine when working under a vehicle. Depleting vehicle air system pressure may cause vehicle to roll. Keep hands away from chamber push rods and slack adjusters; they may apply as system pressure drops.2. Never connect or disconnect a hose or line containing air pressure. It may whip as air escapes. Never remove a component or pipe plug unless you are certain all system pressure has been depleted.3. Never exceed recommended air pressure and always wear safety glasses when working with air pressure. Never look into air jets or direct them at anyone.4. Never attempt to disassemble a component until you have read and understand recommended procedures. Some components contain powerful springs and injury can result if not properly disassembled. Use only proper tools and observe all precautions pertaining to use of those tools.Description And Operation
General
The function of the air compressor is to build up and maintain the air pressure required to operate air powered devices in air brake or air auxiliary systems.Description
Tu Flo Type 400, 500, and 1000 compressors are single stage, reciprocating piston type compressors. Tu Flo 400 (Fig. 1) and 500 (Fig. 2) compressors have two cylinders while the Tu Flo 1000 (Fig. 3) is a V-type design having four cylinders. The rated capacity of all Bendix compressors is their piston displacement in cubic feet per minute when operating at 1250 RPM. The rated capacity of the Tu Flo 400 compressor is 7-1/4 cubic feet per minute. The Tu Flo 500 is rated at 12 cubic feet per minute and the Tu Flo 1000 has a rating of 24 cubic feet per minute.
Figure 1 - Tu Flo 400
Figure 2 - Tu Flo 500
Figure 3 - Tu Flo 1000Tu Flo type compressors have automatic type inlet valves. Their unloading mechanisms are located in the cylinder block and they have no external moving parts. Both air and water cooled type compressors are available. Various mounting and drive adaptations are used as required by different vehicle engine designs (Fig. 4).
Figure 4 - Various Compressor MountingsCompressors are either engine or self-lubricated. The majority used are the engine lubricated types (Fig. 5) which obtain the oil necessary to lubricate their moving parts from the engines on which they are mounted. To meet the requirements of some manufacturers and for field installations, self-lubricated types (Fig. 6) are available. They are compressors having a self-contained oil supply and pumping system.The method of lubricating the moving parts of the compressor is the same in either type. Oil is forced through the oil passage in the crankshaft and out around each connecting rod journal. The turning motion of the crankshaft throws the oil that is forced out at the journals, against the cylinder bores and crankcase walls, lubricating the bores and crankshaft bearings.
Figure 5 - Engine Lubricated Type
Figure 6 - Self-Lubricated TypeThe wrist pins and wrist pin bushings are lubricated in two