David Brown BEARING SET, CONROD, .020 S.57522 1290, 1294, 1390, 1394 K207498One New Aftermarket Replacement Connecting Rod Bearing Set (. 020" Oversize) for David Brown Tractors This . 020" (0. 50mm) oversize connecting rod (conrod) bearing set is used during engine rebuilds and crankshaft regrind services on David Brown tractors equipped with non turbocharged AD4 55 and AD6 55 four and six cylinder diesel engines. The set contains four journal bearings to service all connecting rods in a four cylinder engine block. These