First, forgive me if I am doing this wrong, but in my beat-up '78 / '79 f150 swb 4x4 351M I have a serious leak from the rear main. Is there a way to change the seal without dropping or pulling any main components? I have heard that you can just by dropping the oil pan.

By the way- these forums have been a lifesaver with the gage cluster, charging system, and ignition system being repaired back to factory from a previous butchering.

 

Make sure the valve covers and the oil pressure sender unit are not causing the problem.

 

You can replace the rear man seal after removing the oil pan and rear main bearing cap. The seal that is in the engine may be a rope type and may be stuck pretty tight. There is a tool that is made for removing rope seals, but I have never even seen one or used one. I just used a homemade method. Whatever method you decide to use, just be very carefull not to scratch the crankshaft.

I used the plastic piece of a long tire gauge that shows the tire pressure when it pops out (yes, I destroyed a tire gauge). I then tapped it into the seal groove all the way around until the rope seal fell out. The plastic will conform to the radius of the groove as you tap it in. I realize that this method is outside of the normal professional method, but it works. Oil up the new seal half before inserting it into the seal groove in the block or it will be pretty hard to get it in. I am wrong in assuming you know something about installing seals and know the basics of this such as proper seal orientation, torque specifications and the like?

One last thing is to remove the small spike in the bearing cap if you are using the new neoprene or rubber seal. This spike was used to hold a rope seal from slipping around and not required for the new neoprene or rubber seals. This spike can be knocked out with a small punch. If this spike isn't removed it may cause the seal to press hard against the crank, create a groove and the seal will leak.

 

Purely Ford has it right. It also helps to loosen all the main bearing caps. I, too made a tool for getting the old rope seal out of mine. It wasn't fun or quick, but it did work. Just take your time and make sure you get ALL of the old seal out.

Good luck.

Kevin K.

 

Thanks Purely Ford for all the info. I am used to pulling engines or dropping transmissions to replace seals and all but don't want to on this truck. If I can replace the seal with everything in place but the oil pan I will be happy. Hopefully my clutch is not oil soaked.

 

You're welcome!