Leaking rear main seal

[redgum78]

I have a leaking rear main in one of my Mopars and really do not want to pull and engine just to replace a wick seal. If the engine needed a freshen up I would do it but its perfect other than the leaky seal.

Has anyone had any luck with the magic additives that are supposed to heal everything?

[Chryco Psycho]

Check the oil sender to be sure the leak is not up there

[Brads70]

mine used to weep/leak (or still does? haven't checked in awhile)  but only when sitting for long periods. Once I drive it around the leak stops for the summer.

[redgum78]

mine used to weep/leak (or still does? haven't checked in awhile)  but only when sitting for long periods. Once I drive it around the leak stops for the summer.

This car does sit for fairly long periods between runs but that's not going to change for some time. Gets a run every 8 weeks or so.

[redgum78]

Check the oil sender to be sure the leak is not up there

Have done, its not coming from there unfortunately.

[Cudakiller70]

Just changed the rear seal on a 340 without pulling the engine.

[redgum78]

Just changed the rear seal on a 340 without pulling the engine.

Hey Cudakiller,
How hard was it getting the top halve of the old seal out? I am assuming a combination of pushing one end with something that's not going to damage the crank, pulling the other end with pliers and have someone rotate the crank the same time?

And how about sliding the new one in? Rotate the crank and work it in at the same time?

Any other tips or tricks?

Thanks

[cudabob496]

this cut mine in half. It swells the gasket material

https://www.amazon.com/ATP-AT-205-Re-Seal-Stops-Bottle/dp/B000NVW1LM/ref=asc_df_B000NVW1LM/?tag=bingshoppinga-20&linkCode=df0&hvadid=&hvpos=&hvnetw=o&hvrand=&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=&hvtargid=pla-4584482455317910&psc=1

[kawahonda]

This is one of the reasons I am pulling the engine.

Don't forget that freeze plugs do not last, so if they haven't been replaced yet, those will start to leak soon. Replacing the freeze plugs gives another reason to pull the engine.

[cudabob496]

put a little alumaseal in your coolant to stop freeze plug leaking.

I used it to stop leaks on the manifolf bolts going into the heads.

[Cudakiller70]

I've also have heard of using motor oil for high mileage cars to help with leaks, just be aware of zinc content if you have a flat tappet cam.

I tried pushing the original rope seal around the crank using a chop stick, but it wouldn't budge. Used a sneaky Pete borrowed from a retired Furd mechanic. I only used the tool with the loop at one end and screw threads on the other. I threaded as close to the crank as I felt comfortable trying to grab as much of the seal as I could. Took a good steady pull, didn't rotate crank, wouldn't go at first, but finally let loose and came out as 1 piece.
Cleaned out the seal channel using a pipe cleaner made for guns, it has no metal and a mixture of soft and stiff bristles, won't hurt or scratch anything.
Used a felp-pro 2 piece rear seal with a very light smear dabbed on each seal end where the two halves butt together and a very thing smear on bearing block (flywheel) end only using "right stuff " sealer. I would scratch a mark on block and bearing block just to be sure on reassembly things are going back exactly as it came apart.
I used some break in grease left over from a cam change to lube the seal lip so at initial fire up it wouldn't be dry rubbing on crank at start up. Had no problem installing seal into block, didn't need to rotate crank.
Seal lip iirc goes to the front of the engine..
Also I had to swing steering center link out of the way by disconnecting at idler arm and tie rod on passenger side.
https://www.amazon.com/Lisle-27000-Sneaky-Pete-Tool/dp/B0002SRCJW

[cudabob496]

my freeze plugs have lasted for 25 yrs. But that may be due to the alumaseal in my coolant.

[redgum78]

I've also have heard of using motor oil for high mileage cars to help with leaks, just be aware of zinc content if you have a flat tappet cam.

I tried pushing the original rope seal around the crank using a chop stick, but it wouldn't budge. Used a sneaky Pete borrowed from a retired Furd mechanic. I only used the tool with the loop at one end and screw threads on the other. I threaded as close to the crank as I felt comfortable trying to grab as much of the seal as I could. Took a good steady pull, didn't rotate crank, wouldn't go at first, but finally let loose and came out as 1 piece.
Cleaned out the seal channel using a pipe cleaner made for guns, it has no metal and a mixture of soft and stiff bristles, won't hurt or scratch anything.
Used a felp-pro 2 piece rear seal with a very light smear dabbed on each seal end where the two halves butt together and a very thing smear on bearing block (flywheel) end only using "right stuff " sealer. I would scratch a mark on block and bearing block just to be sure on reassembly things are going back exactly as it came apart.
I used some break in grease left over from a cam change to lube the seal lip so at initial fire up it wouldn't be dry rubbing on crank at start up. Had no problem installing seal into block, didn't need to rotate crank.
Seal lip iirc goes to the front of the engine..
Also I had to swing steering center link out of the way by disconnecting at idler arm and tie rod on passenger side.
https://www.amazon.com/Lisle-27000-Sneaky-Pete-Tool/dp/B0002SRCJW

Thanks all for your input. Cudakiller- Great info mate, thanks for the details, I'll probably have a go this I in the next few months. 

[kawahonda]

my freeze plugs have lasted for 25 yrs. But that may be due to the alumaseal in my coolant.

They certainly don't last 50 years though. LOL

I replaced all the ones I could get to under the car (shitty job, never doing taht again). Most of them had pinholes.