Rear Main Seal Replacement

[ClumsyNinja]

Hello all. Im new here and just picked up a 52 Cranbrook. I have never owned anything like this before, mostly working on newer cars and motorcycles. I look forward to learning and working on this car with my son. It actually runs pretty good right now. Just needs some tinkering.

 

After getting it and driving some, it started leaving lovely little puddles of oil. Putting it up on my friends lift leads me right to the rear main seal. After looking in the service manual and trying to research in the forums and Youtube, I cannot find the answer to if this is a job that can be done without removing the engine. Any help or advice would be greatly appreciated.

[Sniper]

Yes, but you will be pulling the transmission most likely.  It really depends on what engine you actually have, there are at least three different rear main seals that I know of.

 

https://bestgasket.com/rear-main-seals/#chrysler

[ClumsyNinja]

So you don't know which seal you have until you pull it and look?

[Sniper]

It's more like year based, but it's been a long time since yours was built and it may not be the original engine. 

 

See attached for more info.

[ClumsyNinja]

I’m not sure what I’m looking at in those attachments. 
 

I’m 99% sure it’s the original engine. 

[Sniper]

What is the engine number?  That will tell you what engine you have.  Then you can look at the part listing I posted to see what it should use for a rear main seal.

 

But if you do indeed have the original engine the part number is 996350.  Which is also Felpro BS 3141.  You will have to pull the flywheel.

[mlozier76]

I've been looking, but have yet to find a concise answer to the rear main seal being dry or wet on install.  I have a 48 engine that I am in the process of finally getting back together and it has a felt, or rope rear main seal.  Do I need to soak it in 30w oil before install or install dry?  Searches on the main internet are giving both ways, and my manual doesn't seem to shed light on it either.

[Sniper]

The manual doesn't generally tell what not to do, but rather what should be done.  Though there are exceptions and generally those are in the nature of "if you do this (or don't do this) bad things will happen". 

 

For example the 53 and newer Plymouth engines use a rubber rear main seal and the manual is clear about putting grease on the contacting lip.  In both the manual and the training filmstrip it is discussed.  However, the same manual int he very next paragraph makes no mention about putting anything on the rope type seals, can't find a training filmstrip for that.

 

 

[Sniper]

Dug around, found these instruction from FelPro.  If you want to download the PDF, CLICK HERE

 

STEP 1
Remove oil pan, oil pump (if necessary) and rear main cap. Remove
the old rope material from the RMB cap and engine block. Clean the
crankshaft area and inspect for any damage or worn surfaces.
STEP 2
Do not soak the rope seal in oil or any liquid. Hand fit the rope in
the groove of the block and rear main bearing cap. Special tools are
available to compress and pack in the rope. You can also use a socket
on the rope material to roll it into place.
STEP 3
Trim the rope so it’s flush with the rear main cap and block.
STEP 4
Apply a tiny dab (1/8” or smaller) of RTV to the RMB cap rope
seal ends. Apply manufacturer’s recommended sealer to the rear
main cap.
STEP 5
Torque the RMB cap to manufacturer specifications.
STEP 6
Install Fel-Pro gaskets when reassembling the lower engine to
complete the job.

[Eric]

Some good info here also 

 

[Burtbaccarat]

On a 53 they are rubber oem, correct? I’m about to pull my pan and change it as well, I’ve read it’s not a total nightmare to change them while everything is still in the car if the pan is off, of course…

[chris 48 P15]

i did this job on a 1948 plymouth 218 flat six. i had to remove oil pan, last main cap, and flywheel which means trans removal

flywheel has to come off to reach the top on half of oil seal

the seal i used was a new design nylon, a rope seal came of the car

there are a couple of threads about this

no leaks yet