pcxt21 Posted October 1, 2023 Report Share Posted October 1, 2023 Hi all as the title suggest I'm struggling with getting my molded 2-piece brummer style rear main to actually seal on my freshly rebuilt 251. On my first 2 attempts i used RTV between the seal haves as is usually suggested for later v8 and i6s that use this style of seal with no success. I still get a steady drip from the seal (Best Gasket 3675) so clearly I'm doing something wrong. My reprint of the service manual only has some basic instructions for a single piece version of the seal that seems to be discontinued, so i ask what is the best practice for successfully installing these style seals in our engines? Should i lube it with assembly grease? Or use glycerin soap? I'm guessing the ends of the seal need to be dry but should i be lining them up with the face of the bearing cap or rotating them so they sit inside a cap? Any insight is greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Sniper Posted October 1, 2023 Report Share Posted October 1, 2023 Did you install the side seals too? Did you install the seal so that the open side of the lip faces in? Should look like this (not a mopar application shown, but seal direction is the same) Quote Link to comment Share on other sites More sharing options...
pcxt21 Posted October 1, 2023 Author Report Share Posted October 1, 2023 Yes i've been orienting the seal with the open side of the lip in, ive been using the included side seals with a bit of sealant to hold them in place but my leak is definitely from the center of the seal its self, not from around the cap. Quote Link to comment Share on other sites More sharing options...
Dave72dt Posted October 1, 2023 Report Share Posted October 1, 2023 Does the crankshaft have a groove worn in it wear the seal would ride? Quote Link to comment Share on other sites More sharing options...
DJK Posted October 2, 2023 Report Share Posted October 2, 2023 Have you checked for excess clearance on the rear main bearing? Quote Link to comment Share on other sites More sharing options...
pcxt21 Posted October 2, 2023 Author Report Share Posted October 2, 2023 Hi all, this engine was recently rebuild, i did all the final assembly, crankshaft was polished along with sealing face for RMS on rear journal, mains Mic'd and plasti-gauged in spec during final assembly. This leak is the only issue ive had during and after break-in. Quote Link to comment Share on other sites More sharing options...
D35 Torpedo Posted October 3, 2023 Report Share Posted October 3, 2023 Is it possible the sealing surface is ground undersized to the point that the seal ID is to large? Quote Link to comment Share on other sites More sharing options...
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