Brand New Plate Surplus Caterpillar part number 2856391 This plate, bracket, holds the Compressor to the engine, and has a slot which can be used for adjustments in and out. Its fitted with a square opening, which an extension bar can be placed into and used to apply force to ensure that the vee belt is taut. Used on Compressor Groups on these machines. Wheel-type Loader Compact Wheel Loader 906 MER Wheel-type Loader Compact Wheel Loader 908 TAR