BELT 4F7956 - 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
Fig. 1-Piping Diagram Showing a Compressor in an Air Brake SystemGeneral
The Tu-Flo 300 Compressor is primarily used in air over hydraulic brake systems (Figure 1). Another use for this type compressor is in air supply systems for service trucks used for inflating tires, cleaning, driving tools, etc.Description
Figures 2 and 3
Fig. 4-Compressor Oiling SystemsTu-Flo 300 Compressors are single stage, reciprocating piston types. Their rated capacity in piston displacement when running at 1250 RPM is 4 cubic feet per minute. They are designed for vertical mounting and are fitted for belt drive only. Only air cooled type Tu-Flo 300 Compressors are made.Tu-Flo 300 Compressors have automatic type inlet valves. Their unloading mechanisms are located in the cylinder block and they have no external moving parts.Tu-Flo 300 Compressors are either engine (Figure 2) or self-lubricated (Figure 3). If engine lubricated, they receive their oil supply for lubrication from the engines on which they are mounted. Self-lubricated compressors contain their own oil supply and pumping system. The method of lubricating the moving parts is the same in either type (Figure 4). Oil is forced through an oil passage in the crankshaft and out at each connecting rod journal. As the crankshaft turns, the oil that is forced out at the journals is splashed against the cylinder bores and crankshaft bearings.Die cast aluminum connecting rods and cast iron pistons are used in the Tu-Flo 300 Compressor. The wrist pins are lubricated by oil dripping from a drip-boss on the piston into a catch-funnel at the top of the connecting rod and through a drilled passage to the wrist pin and its bushing.A name plate is attached to the crankcase of all Tu-Flo 300 Compressors. It shows the piece number, compressor type, and a serial number. The nameplate with a black background indicates a new compressor; if the background is red it indicates that the compressor is a factory reconditioned unit. The piece number identifies the compressor and it is the number used when reference is made to a particular unit. The serial number and type are