Rear Main Seal Problems

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Toby Brown
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Rear Main Seal Problems

#1 Post by Toby Brown »

Getting the car ready for a fall trip to Arkansas and decided to have the rear main seal replaced as it has been leaking all summer. Pulled motor and found that the flywheel had a failed speedy sleeve and two grooves had worn into the flywheel hub. Decided to purchase a new flywheel and replaced the seal and the flywheel and put everything back together. Drove the car to our local Kansas City Porsche Club breakfast Saturday morning and found a puddle on the pavement upon my return. Got home and called my mechanic to give him the bad news. Looks like we have to do the whole thing over again. Rennlist had a discussion about multiple failures occurring with current main seals. We used a heavy duty brown seal that had been very reliable for my mechanic. Have any of you had problems with main seals lately and if so what have you done and what seals have you used. Thanks for your help

Peter Poulikakos
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Re: Rear Main Seal Problems

#2 Post by Peter Poulikakos »

Hi Toby
I think this the seal you require, it should have a single lip not a double.
Im sure someone will chip in to confirm.

Peter Poulikakos
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Re: Rear Main Seal Problems

#3 Post by Peter Poulikakos »


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C J Murray
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Re: Rear Main Seal Problems

#4 Post by C J Murray »

Use a single lip seal or cut off the outer lip of the 2 lip seal.

Did you check crankshaft end play? It seems like you could have more of a problem than just a seal although the seals are a common problem.
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Tim Berardelli
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Re: Rear Main Seal Problems

#5 Post by Tim Berardelli »

F/W seal pictured is for a 40hp VW and is incorrect-P/N 111105345 for a 25/36hp VW is correct.

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Vic Skirmants
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Re: Rear Main Seal Problems

#6 Post by Vic Skirmants »

I have never had a flywheel seal fail; race or street.
Something else must be going on. Cliff's comment on end-play may be the clue.

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C J Murray
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Re: Rear Main Seal Problems

#7 Post by C J Murray »

Vic is correct in that once a 1 lip seal is in and working correctly they seem to never fail. The only failure that I have had was with a 2 lip seal. I had previously used those successfully but after one failure I never use a 2 lip seal now.
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Olivier Auvray
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Re: Rear Main Seal Problems

#8 Post by Olivier Auvray »

C J Murray wrote:Vic is correct in that once a 1 lip seal is in and working correctly they seem to never fail. The only failure that I have had was with a 2 lip seal. I had previously used those successfully but after one failure I never use a 2 lip seal now.
on high speed applications (like a flywheel seal) a lip needs oil/grease to stay "alive". If you use a 2 lips seal, the second lip doesn't see oil, burns quickly and overheat the first lip ............. the result is well known: a leak!
One option is to use a seal with one oil lip plus one dust lip (that doesn't touch the hub/flywheel) but on a 356, the dust lip touches the radius of the flywheel and the result is the same : oil leak!

Peter Poulikakos
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Re: Rear Main Seal Problems

#9 Post by Peter Poulikakos »

This must be the seal Tim has quoted, my mistake

https://www.wolfsburgwest.com/cart/Deta ... =111105245

Mike Horton
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Re: Rear Main Seal Problems

#10 Post by Mike Horton »

Yes, that is the correct seal. A similar appearing seal, from other of our vendors, is the brown Viton, but has the double lips. We ran into this issue when I helped my Friend Spike Jones, with his '58 Cab engine, earlier this summer. Fortunately, I had ordered the seals Tim had posted for us on the 912 Registry, and had one on hand.

I've used the steel speedy sleeves successfully, in the past, and not had issues. I agree with C.J., & Vic, again, in this one. Those two agree on more than not, they just have fun here, my $.02, entertainment for the rest of us...
Mike

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Toby Brown
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Re: Rear Main Seal Problems

#11 Post by Toby Brown »

Yes Vic the end play was checked and properly set with a new shim for the new flywheel. I dont remember if the brown seal was a double lip. That makes sense. Guess we’ll find out when we tear it down again. Thanks for all of your help. By the way where have you been buying your seals?

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Vic Skirmants
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Re: Rear Main Seal Problems

#12 Post by Vic Skirmants »

I simply use the Reinz kits from Stoddard, or buy the seals individually from them also.

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Toby Brown
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Re: Rear Main Seal Problems

#13 Post by Toby Brown »

We went with Vic’s recommendation and used the Reinz seal and rechecked everything. So far no leaks but will have to take the car out again for another test run. Plan on driving about 6 hours down to the Porsche Palooza in Eureka Spring, Arkansas. One of the best regional driving tours in the Midwest with absolutely fantastic roads. Over 250 cars signed up and some 450 people will be attending. Let’s hope this leak is history. Thanks for all your help. Good news is that we can drop an engine in pretty quick time now!

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Toby Brown
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Re: Rear Main Seal Problems

#14 Post by Toby Brown »

After taking Vic's recommendation of the Reinz seal we thought that it was finally a winner. After a hour long test run we found that it was still leaking. We were very careful in the Reinz seal installation and took our time with no luck. What else could be going on to cause this leak. The engine now has about 1000 miles on it and is running very strong. Any ideas?

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Re: Rear Main Seal Problems

#15 Post by Dan Epperly »

Toby Brown wrote:After taking Vic's recommendation of the Reinz seal we thought that it was finally a winner. After a hour long test run we found that it was still leaking. We were very careful in the Reinz seal installation and took our time with no luck. What else could be going on to cause this leak. The engine now has about 1000 miles on it and is running very strong. Any ideas?
Check the face of the crank where it mates with the flywheel. I had a VW crank that had a slight deformity there and caused a leak.
I suppose the same could happen on the flywheel face too.

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