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Rear Crank Seal replacement. Without dropping the oil pan?

kumfasa

Well-known member
Joined
Feb 28, 2015
Messages
125
Location
Tauranga, New Zealand
Hi Guys,
I'm changing the transmission in my car and the rear main seal is leaking a little bit.

Back story is: I put a new clutch in about 2000 miles ago and while the crank seal area was oily I didn't know if it had come from one of the oil leaks above or the crank seal itself, so I just cleaned it up and put the new clutch in.
Well I have the tranny out and it does appear to be leaking a little oil onto the back of the flywheel (There are no more oil leaks above that could contribute) so I figured I would change it "while I'm in there".

Can I do it without dropping the oil pan?

Engine is still in the car and would love not to have to drop the pan if I don't have too.

Thanks in advance.
 

89Mirageman

Well-known member
Joined
Jul 5, 2006
Messages
2,502
Location
Stantonsburg, NC
I've screwed a screw in a seal before to remove it. Never done it before on the rear main seal but don't see why its not possible.

Also you might be able to just remove the oil pan bolts from that rear main seal housing, replace the seal and then reseal that part.

Either way pulling the trans is an involved job and I've learned in the past whenever I cut a corner that 99.9% of the time it just creates more work.
 
Last edited:

iceman69510

Turn Right Racing
Staff member
Joined
Mar 5, 2001
Messages
10,922
Location
Michigan
I think it is doable. If you remove it without removing the housing, pressing it back in evenly will be the challenge. Diameter is a bit big.

While I like Chris' suggestion to just remove the few oil pan bolts and remove the housing, I would be a bit leery of ending up with a leak where the old sealer and new would interface.
 

89Mirageman

Well-known member
Joined
Jul 5, 2006
Messages
2,502
Location
Stantonsburg, NC
I agree, it might work or it might not. I'm getting to the age where I absolutely despise doing the same job twice. Think I'd bite the bullet, drop the pan and do it right. But that's just me.
 

kumfasa

Well-known member
Joined
Feb 28, 2015
Messages
125
Location
Tauranga, New Zealand
Thanks Guys,
I cant see a reason why I wouldn't be able to reseal the crank seal housing so long as I clean the area well and use some good RTV.

Has anyone out there actually replaced this seal without removing the pan? How did it go?
 

thomcasey

Well-known member
Joined
Sep 24, 2014
Messages
907
Location
Indianapolis, IN
I have, and I ended up with a leak. It wasn't a bad leak, but I don't like drips.
 

kumfasa

Well-known member
Joined
Feb 28, 2015
Messages
125
Location
Tauranga, New Zealand
Just for anyone interested. It seems like there was some confusion in the above comments.

On a 6 Bolt motor the rear main crank seal is pressed into the back side of its own aluminium housing and cannot be removed without removing the housing from the motor.

The housing shares two oil pan bolts and seals against the block and the oil pan. I have read that some poeple have had trouble sealing against the pan after removing and re-installing the housing because it no longer has a continuous bead of sealant around the oil pan.

Well I gave it a go.
After removing the seal housing I removed all RTV that could be seen and cleaned the block and oil pan meticulously and gave it a light scrub with a scotchbrite pad.
Using my finger I applied a 1-2mm thick layer of RTV to the pan and block surfaces at the bottom edge of the seal housing. It has its own gasket to seal against the block. I didnt want to put too much here as it may get puched into the engine when installing the seal housing. Its a very small gap between the pan and the housing.

I installed the new oil seal into the housing by tapping it in evenly with a large socket. Attached the housing gasket with a couple of dabs of rtv to hold it in place, oiled the seal and crank and slid it on. Buttoned up all the bolts being very careful not to over torque the oil pan bolts (7 ft/lb) as this can distort the pan and cause a leak.

The Results...NO LEAKS.

I have put a few hundred miles on it since install and I have had a good look around the area after removing the inspection plate and its dry as a bone.

Surface prep and having a good think about how much and where to put the RTV is the key. Sorry didn't take pictures along the way but here is the finished product. You'll get the idea.


 
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