Main Bearings - Standard - Set Fits John Deere 2355 2350 2520 2020 2510 2030 255One New Aftermarket Replacement Standard Main Thrust Bearing Set Fits John Deere Tractors, Combines, and Industrial Equipment This standard (STD) main thrust bearing set Fits John Deere 3, 4, and 6 cylinder gasoline and diesel engines with a standard 3. 124 inch main journal diameter. Order one set per engine. The set supports the crankshaft main journals inside the engine block and is a direct replacement for worn or damaged bearings during engine