M-Head Rebuild Kit The is a rebuild kit for the M Type Bridgeport head. It contains the V-Belt, (4) Spindle Thrust Bearings, and (2) Upper Head Bearings. Individual items in this kit may not be retuned for refund unless the entire kit is returned for refund. Kits are prepackaged and can not be sold with individual parts taken out. If you do not need the entire kit we can sell you the parts individually.