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Newbie question

Calebjr

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May 24, 2025
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Location
Nampa, ID
Hi all,

I'm a newbie from Nampa, ID. I own a 70 Road Runner 440 engine having trouble with the rear main seal leaking. Open to suggestions on how to fix.

Many Thanks
 
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Hi all,

I'm a newbie from Nampa, ID. I own a 70 Road Runner 440 engine having trouble with the rear main seal leaking. Open to suggestions on how to fix.

Many Thanks
Pull the oil pan, pull the rear main seal holder thing (brain not working yet..) here is a vid showing it apart... you can do it in the car.. it's a horrible job but has to be done.. On the upside i don't believe you have to remove the main cap...



Here is a second video so you can see it..

 
Welcome to FBBO from Georgia
 
Welcome. Per your post, you own just the engine, not the entire car?
Let’s see pics.
You may want to post your question in the correct forum for better response. Or better yet, search the site because there are a lot of posts about rear main seal replacements here. Good luck!
 
Get rid of the factory seal retainer and get an aftermarket billet replacement before replacing the seals. I had to do this to remedy an oil leak on the 426 Wedge I had in one of my cars
 
Seal Retainer! That's the words i couldn't find :) BTW.. what was wrong with the stock one that a billet fixed? i never had one leak.. but i pray at the altar of black RTV :)

Get rid of the factory seal retainer and get an aftermarket billet replacement before replacing the seals. I had to do this to remedy an oil leak on the 426 Wedge I had in one of my cars
 
Welcome from PA!

The rear main seal is a bit tricky, but the key is to measure where the seal is relative to the block, and make sure the retainer is in the same relative position so the upper and lower seals are in the same plane. The second key thing is to make sure the side seals stay all the way down when installing the retainer. Many people cut off the side seals if they stick up, figuring that is extra. But it is not: it means the lower part of the seals aren't all the way down so you will have a leak. If your side seals stick up, pull out the retainer and do it again until it is right!

Good Luck
 
Welcome from Alabama. Pictures of said 70 RR? Rear main seals are tricky, but some good advice in previous posts.
 
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