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General TR Rear Main Seal--Minor Problem


Luke Skywalker
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I just tried unsuccessfully to install the Viton rear main seal, so I thought it best to start a new thread due to the specific nature of the problem. I'll try again and get it, but here is what happened:

a) The holes in one of the halves of the assembly are such a tight fit to the holes in my engine block, that I'm scoring the internal bore of two of the screw holes in the fitting just tightening it in, and there's no sense in proceeding since when I'm done the half in question will have no play or ability to achieve adjustment. In fact, it's going in with one side too high; and

b) All the fiddling allowed the silicone to start setting too quickly and I don't trust the bond.

I'm inclined to use Wellseal the next go around, but what do I do with that rear main seal?

I can see gently filing two of the screw holes just a slight bit larger with a round file. I don't want to drill anything.

I have to assume I'm not the first to encounter this issue? Filing the screw holes a bit should be no big deal?

Thanks in advance for any advice.


Great Pumpkin - R.I.P
Filing the holes should be no problem, but check the fit onto the mandrel first. It may be that the casting got distorted during shipping or something.


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Are you talking about the felt and gasket shellac or where the two halves of the rear main meet KVH? It has been a year or so since I put a mad max seal in, so I posted what the people said and they really helped me.


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You are using a new blue anodized housing correct? If so I think filing is appropriate but as Randall notes check the mandrel. When the kit first came out it reused stock housings but the new casting may not have the holes sized quite right.


Luke Skywalker
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Yes, I have the new, blue rear main seal housings, I assume aluminum. I found a post from Christian Marx mentioning use of silicone to seal where the "flats" of the housing meet the block and bearing cap. I think the old school is Wellseal which I'd prefer to use. In fact, the post mentioning silicone showed the old style gray aluminum. I could also use Permatex High Tack for the sealer. High Temp Red Silicone didn't seem to adhere well to the highly polished blue aluminum surfaces of the new style main seal.

As for the felts, those are another issue. I plan to soak those in Permatex High Tack or Wellseal, mainly since that's what I have in my little shop.
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