Author Topic: Rear main seal question  (Read 4241 times)

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DCEPTCN

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Rear main seal question
« on: March 27 2006, 06:21:04 PM »
I think we were discussing this when last we had beers, but I need a refresher. My rear main seal has been crappy for a long time, but recently it kinda seems like it got a little worse. I keep a drip pan under the ol' girl and there's always oil on my crossover pipe. No biggy, really. I've seent the gnttype.org write up on how to replace it and it looks easy enough. What I'm wondering is- there really isn't any detriment or benefit regarding the rear main seal's condition, is there? I mean, if it's bad it'll leak, but there's no mechanical harm or anything in just saying f- it and living with an oil leak, right?

Offline Recklessrob

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Re: Rear main seal question
« Reply #1 on: March 27 2006, 06:48:58 PM »
For a small leak, no biggie. If it gets real bad, you
could lose your engine. With the first 3.8 that I had
in my Pontiac I lost the rear main in the parking
lot of the local Dunkin Donuts. It covered the lot with oil.
I walked to a near by store and bough 5 qts of oil. That
was just enough to get me the 2 miles to my house!
If that happened on the highway, I would've lost the engine for sure.
Also keep the crossover pipe as clean as possible. Oil hitting
a hot pipe is a pontential fire hazzard.
Rob

DCEPTCN

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Re: Rear main seal question
« Reply #2 on: March 27 2006, 06:59:07 PM »
It seems to be pretty slow and I only get a few drops on the crossover that burns off immediately at start up. What you're talking about is what I was interested in finding out.....so it could/eventually will go out altogether? Dammit. Then it might be worth the hassle.

Offline SuperSix

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Re: Rear main seal question
« Reply #3 on: March 27 2006, 07:10:50 PM »
Quote from: "DCEPTCN @ Mon Mar 27, 2006 6:59 pm"
It seems to be pretty slow and I only get a few drops on the crossover that burns off immediately at start up. What you're talking about is what I was interested in finding out.....so it could/eventually will go out altogether? Dammit. Then it might be worth the hassle.


It just may go that quick, but not often. It will get progressively worse, will continue to coat the undercarraige with oil (and stain the exhaust piping), and will eventually need to be replaced.

It's not a fun job, but a good day job. I followed the instructions on GNTTYPE.org religiously, (twice) and it works pretty well.

Use a neoprene gasket, make sure to silicone wher they say to, and don't use the little metal pins in the kit.

Helps to have some house A/C wire to use to push out the old rope gasket.

Aslo, make sure you have a GOOD torque wrench, as you will need to re-torque the rear mains.

Get a new oil pan gasket too.
'87 GN, 60lb, TA49, THDP, FTP cam, T+ lots o' shit - SOLD
'07 Ford F150 Lariat 2WD, 5.4L 3v - 255k
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Offline Recklessrob

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Re: Rear main seal question
« Reply #4 on: March 27 2006, 10:17:37 PM »
A little trick that I use to get the old rope seal out is:
to get a medium sized nylon zip tie, cut the end square,
hold it firmly against one end of the seal while having
someone turn the crank, and it will usually come right out.
And with the zip tie, you don't have to worry about scoring the crank.

Where your engine was recently rebuilt, it'll likely have a neoprene seal
already. This method still works.
Another tip is to put some assembly lube on the seal
lip to keep it from burning up from a dry start up.
With the seal, there'll be a little piece of plastic. that's used
to help during installation by allowing a smooth surface for
the outer part of the seal by keeping it from catching on the edges
of the block.

S6, whats the problem with the pins ? I've never had a problem from using them.
Rob

Offline 87natty

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Rear main seal question
« Reply #5 on: March 27 2006, 10:24:47 PM »
Main seal wasn't too bad... I think finagling the pan off was the worst part. From there it's pretty straight forward. I also just siliconed the piss out of the sides as per gnttype.org, I never questioned why, just did it. 3 years, daily driven, dry as a bone.
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DCEPTCN

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Re: Rear main seal question
« Reply #6 on: March 28 2006, 01:04:56 PM »
Alright, sounds like I'll be doing it soon. I need to get down there and take a close look at it though, 'cause at this point I'm talking about some hypothetical gasket that I've never even seen.

Offline 87natty

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Rear main seal question
« Reply #7 on: March 28 2006, 01:35:29 PM »
It's like a rubber bearing. I think that's the best way to describe it.
My 1958 Mamiya can beat up whatever camera you just wasted your money on.

 

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