How do I replace the rear main seal on my 1972 F-250? I have a 390v8 with a regular cab long bed. I believe I have a C6 transmission.

 

The RM seal in the 360/390is a 'split' type seal,, and isof the 'rope type' material (if original) or 'wick' seal as some refer them as.. To replace the RM, you have to raise the engine and drop the oil pan, thenremove the rear main bearing cap.. If it's the original seal, them you'll have to pull the old rope seal out.. Easy enough on the bearing cap, but 'can' be a bit harder on the upper portion and must be carefully removed without 'knicking'or scratching the bearing journal/seal lip area.. There's a seal remover kit that comes with a screw type puller (you can improvise) that gets a bite on the seals end.. Not always successful though,, and usually requires some picking at the seal, or taking in out in pieces.. Sometimes pushing from the other side while pulling on the tool, including turning the crank helps.. Loosening the main bearing caps slightly for some extra clearence if it's a fighter The replacement seal will be a split 'neoprene-rubber' set that you can just gently push/roll into position, sealends/cap and your ready to install the pan.. The rear bearing cap also has cap 'seal strips'that have to be installed during the bearing cap replacement.. The neoprene unit must be compressed against the crank slightly and then rolled carefully into position or it can 'peel' some of the outside diameter area off the seal from the sharp edges of the block/bearing cap surface and may cause the new seal to leak..