Rubber Rear Main Seal

[OlsonsGaskets]

I'm trying to reproduce New Rubber Rear Main Seal kits for the V6 and V12 engine.

In order to do this I am in need of 2 Rear Main Bearing Caps. 1 of these Rear main caps will be destroyed in the process of reverse engineering the seal. Since this is the case I don't want to borrow caps from engines that are in the process of being rebuilt. I would prefer to buy (or trade?) caps from junk blocks so that I'm not at risk of losing something that is irreplaceable.

Does anyone out there have junk blocks that we can steal the rear main cap out of?

[63gmc4x4]

I have some caps, I never look at this but I would love a rubber rear mail seal

[OlsonsGaskets]

Are any of the Rear Main Caps from Junk blocks? My manufacturer will end up destroying 1 of the caps (i.e. they cut it in half to measure the journal) in the process of reverse engineering the rubber rear main seal.
Feel free to give me a call at the shop, you can get the phone number on the Olson's Gaskets website.
Thanks,
Richard

[tbucketnut]

Thanks Richard for your work on this. Ive been by to see you guys a couple times in the past. Appreciate everything you do to keep our hobby trucks on the road. Steve

[Prowbar]

What might be interesting to know is that a rubber rear main seal has been produced in the past. I just scored one on Ebay, they are new old stock.

The number is Detroit Gasket 17091 (there are more numbers, BS40048 is used also, but in conjunction with the rope seal)

This is a lip seal, consisting of two halves with a steel backing for rigidity. I'll upload some pictures later today. I'd be willing to help out with any info you may need, as a good rear main seal saves a lot of grief and oil soaked driveways.

[Prowbar]

Here are some pictures of the rear main seal.

[63gmc4x4]

Originally Posted by Prowbar

Here are some pictures of the rear main seal.

The fel pro number is correct but it's a slim chance it's rubber, I've ordered 4 of the same number and I got lucky and one was rubber the rest are rope, I think it was a later design

[Prowbar]

Originally Posted by 63gmc4x4

The fel pro number is correct but it's a slim chance it's rubber, I've ordered 4 of the same number and I got lucky and one was rubber the rest are rope, I think it was a later design

I assume so too, when was the last time you ordered the rear main seal and got the lip seal?
Maybe they are discontinued, maybe not? I'll see if I can reach out to Fel Pro and ask them.

[63gmc4x4]

6 years ago

[Prowbar]

Yeah, that's a long time ago.

Just got off the phone with Fel Pro, the guy said they only stock the rope seal and denied the fact that the lip seals had the same part number, which clearly isn't true.
At least he could find the GMC V6 engine in his computer.
I'm assuming the lip seals have been discontinued. They still produce the rope seal, so if you order one, that's what you get (P.S. the rope seals from FelPro are crap...)

If OlsonsGaskets can produce a quality lip seal then everyone would benefit!