Replace old rear seal?

[cobragene]

428 fe I have a pin hole leak in my cast aluminum oil pan and of course it’s blowing back on bell housing, inside bell is dry, no oil running down from up top I did a dye test, I am going to drop trans for another reason and seal the oil pan but while i am in there should I also replace the 23 year old rear main seal? What type of sealer should I use on the pan?

[patrickt]

I've used JB Weld on that same sort of leak on non-Cobra related repairs. And I wouldn't replace a rear seal unless it was leaking.

[incoming]

I beg to differ. If it's staring me in the face and cheap to change, I change it.

Please don't use JB Weld

[incoming]

I beg to differ. If it's staring me in the face and cheap to change, I change it.

Please don't use JB Weld

[twobjshelbys]

I'd replace it since you're in the neighborhood.

[DanEC]

I vote with Patrick on the rear seal just from what I’ve heard from builders of FEs and how sometimes it’s difficult to get a rear seal tight. If it’s not leaking, why test the Gods. See what Brent thinks.

[patrickt]

Originally Posted by DanEC

I vote with Patrick...

That's almost always the right thing to do. I'm betting Brent will agree. And I'm betting he'll like the JB Weld fix as well. If that's the case, Incoming will have to then stand on a soapbox and sing the ClubCobra pledge song.

[Argess]

It's difficult to change without removing the crank, but can be done. Twice I've been in the process of rebuilding an FE when I forgot to install the rear seal before installing the crank. I tried to slip the seal-half in there, but the crank had to come out and this was with the block upside down on an engine stand. Also, those side-seals can be fiddly. I wouldn't be comfortable torquing the rear bearing cap while under the car either. So... leave it if it isn't leaking. A tiny leak (as in no drips, but a little damp with oil)? Leave it, or take the engine out.

[DanEC]

I think FE rear mains are like Mopars with a retainer, main seal and side seals. I just replaced one on a 426 Hemi where the side seals were leaking. I could do it (not with a rope seal) without disturbing the crank but it was a real pain. So far-so good, but if it hadn’t been leaking I never would have touched it even though I still had to pull the pan to replace it and the pickup.