Main Bearings - Standard - Set Fits Case 1200 1294 1390 1290 David Brown 996 121One New Aftermarket Replacement Standard Main Bearing Set for David Brown (Fits Case) Tractors This standard size crankshaft main bearing set is designed for the David Brown AD4 49 and AD4 55 four cylinder diesel engines used across the David Brown 900, 1200, and 90 Series tractors as well as their Fits Case badged equivalents. Sold as a complete set without thrust washers. Use this set when your crankshaft has been polished to standard size; oversize