AIR BRAKE COMPRESSOR INLET CHECK VALVE (INFORMATION)

SUBJECT: AIR BRAKE COMPRESSOR INLET CHECK VALVE

MODELS: 1990-91 C5H, C6H, AND C7H TOPKICK/KODIAK MEDIUM DUTY TRUCKS WITH BENDIX BX-2150 COMPRESSOR

In above applications the BX-2150 Compressor is equipped with an inlet check valve and will continue to "pump" air out the open air dryer purge valve during the entire purge cycle. This action is not detrimental to either the compressor or air dryer and occurs only when a single cylinder compressor is equipped with an inlet check valve. This occurrence is the result of the inlet check valve taking over the function of the compressor inlet valve during the unloaded mode.

INLET CHECK VALVE

The inlet check valve is used to prevent inlet oil misting during the unloaded cycle. The inlet check valve is mounted directly at the inlet cavity of the compressor. It consists of three parts, the inlet gasket, the inlet check valve reed, and the inlet check valve (see Figure 1). During the compression cycle, the inlet check valve reed is drawn away from its seat uncovering three inlet holes allowing air to flow into the compressor inlet cavity. A machined stop in the cylinder head inlet cavity limits the trav- el of the inlet check valve reed. In the unloaded cycle, the inlet check valve reed rests on its seat covering the three inlet holes. Air from within the compressor is prevented from exiting the inlet cavity.

The inlet check valve may only be used in conjunc- tion with cylinder heads incorporating the machined inlet check valve stop in the inlet cavity. Inlet gasket, Bendix part number 243430, is required since its thickness contributes to the minimum reed travel required. Either side of the inlet check valve reed may be installed next to the gas- ket; however, the free end (tip) of the inlet check valve reed must coincide with the machined inlet cavity stop in the cylinder head. The inlet check valve seat must be installed so that the two 'half moon" indentations are on the side facing the inlet check valve as illustrated in Figure 1.

The function and appearance of the check valve can be found in the Bendix BX-2150 Service Data Manual SD-01-331. This manual can be obtained by contacting :

ATTENTION:

TECHNICAL SERVICES DEPARTMENT BENDIX HEAVY VEHICLE SYSTEMS 901 CLEVELAND STREET ELYRIA, OH. 44036 (216) 329-9000

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