SHOE(MASTER) 3P1128 - Caterpillar

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Wabco 250 cc Air Compressor
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Wabco 318 cc Air CompressorThe Wabco 250 cc air compressor and the Wabco 318 cc air compressor have these features.
A cast iron cylinder block
A steel valve body
An aluminum cylinder head
The intake valve is a reed valve.
The discharge valve is a reed valve.
The air compressor is lubricated by engine oil.
The air compressor is controlled by the governor and the unloading mechanism of the compressor. The governor maintains the system pressure for the air brakes. The system air pressure is preset at minimum levels and at maximum levels.
The governor is mounted remotely from the air compressor. The port for the governor is located on the crankcase of the air compressor.
The air compressor has an unloading system that conserves energy. When the air compressor is in the unloaded position the power requirements for the air compressor are reduced by approximately 80 percent.
The cylinder head of the air compressor contains the inlet valve, the discharge valve, the unloader valve, and the relief valve. The cylinder head of the air compressor contains a pressure relief valve that is integrated into the cylinder head.
The relief valve protects the air compressor from damage if the discharge line becomes blocked or the governor line becomes blocked or if the compressor unloader valve would fail. The relief valve prevents the compressor from exceeding 1724 kPa (250 psi).
A replacement kit for the cylinder head is available.
The Wabco 250 cc air compressor has the capability to drive accessories. This feature allows accessories to be driven from the rear of the air compressor.
The Wabco 318 cc air compressor does not have the capability to drive accessories.