• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Another Rear Main Seal Thread

Get a one of those cheap endoscope cameras that plug into your phone or laptop
and fish it around and see where the leak is. get one with lights around the lens
and you can see anywhere. you can even take video and still pics.
 
@zyzzyx I'm not sure if your comment is directed at 1969VAGTX or me. I did try with a bore scope but I can't get it up between the block and the flex plate.
 
If you use stock retainer grind these nubs a little.View attachment 1421964
With stock bolts you need to grind the point off the bolt so the retainer sits flat in some cases, the retainer is thin there so I do the bolts. The retainer can also hit the rear main cap before the ends of the seal line up causing a leak, you may need to machine the cap or seal retainer, where the little squiggles are. Also be sure your rear main cap is pushed forward so the relief machined in the rear is lined up.

20230409_180321.jpg


20230409_180018.jpg


20230409_174857.jpg
 
That is another good thing about having 3 pedals... you can drop the cover and look right up at the seal and retainer and see if coming from there..

You can also buy some UV dye and a leak detection kit pretty cheap from some parts stores. Advance sells the kit for like $25 and the dye for like $10


Besides, aren't old Mopars like dogs and mark their territory when they park?
 
You also need to line up the seal ends perfectly, then stamp the retainer sowhen the engine is in the car you know where to put the retainer. In this blocks case it need to be .020 further forward on the passenger side, and offset .005 to the drivers side. Doing it in car will be very difficult, that's why rope seals work so well. Even with everything I do, it can still leak as the block can be machined wrong and the seal does not quite touch the crank, no way to see that in the car. I always set the engine on its back and pour oil in and test for leaks.

20230409_174532.jpg


20230409_174510.jpg


20230409_174457.jpg


20230409_174442.jpg


20230409_030103.jpg
 
Last edited:
With stock bolts you need to grind the point off the bolt so the retainer sits flat in some cases, the retainer is thin there so I do the bolts. The retainer can also hit the rear main cap before the ends of the seal line up causing a leak, you may need to machine the cap or seal retainer, where the little squiggles are. Also be sure your rear main cap is pushed forward so the relief machined in the rear is lined up.

View attachment 1450210
I have heard of others mentioning grinding these spots on the retainer. My question though is why would that be necessary since the factory never had an issue there in the first place? Stock retainer, bolts, and block.
 
I have heard of others mentioning grinding these spots on the retainer. My question though is why would that be necessary since the factory never had an issue there in the first place? Stock retainer, bolts, and block.
Because the factory used a rope seal, if the retainer was out of alignment .020 because of the bolt it did not matter, with a lip seal. 020 will be a leak 100% of the time. Some blocks have major crank to seal misalignment, as in the seal will not touch the crank, so you epoxy some steel in the groove on that side, or some other hack, or use a rope.
 
Last edited:
Just fixed another buddy’s rear main seal, motor in car. He’s tried it twice already and the last time time a fast fish 1 piece seal. I guessed it was leaking like mine. In between the seal and upper part of the block. We put a rope seal in it and it quit leaking. We still used the Fastfish retainer.
 
Just fixed another buddy’s rear main seal, motor in car. He’s tried it twice already and the last time time a fast fish 1 piece seal. I guessed it was leaking like mine. In between the seal and upper part of the block. We put a rope seal in it and it quit leaking. We still used the Fastfish retainer.
I think in car a rope is your best bet, pic of the install tool.

20230415_105146.jpg


20230415_105221.jpg
 
Before I begin, I have read through a bunch of the threads here about replacing the rear main seal. I also watched @Beekeeper videos on YouTube. We are getting ready to try to address the rear main seal in my GTX once and for all. The catch is we are doing this with the engine in my car. So here are my options, please provide your recommendations.

The car currently has a billet retainer in the car. I suspect the problem may be related to what @Beekeeper discusses in his videos. I also purchased a Fast Fish retainer and seal. And we have secured an original retainer. I am leaning towards installing the Fast Fish since a number of guys at Carlisle recommended that route to fix the leak, but I am curious if anyone has actually installed that one piece seal effectively with the engine in the car? When we pull the billet retainer out, I will check the clearances to see if it needs to be machined along the lines of the video recommendations as well.

Given all of these factors would appreciate some recommendations. Thanks.
Rope Seals work best. Check the finish on your crank. I WASTED massive time and effort on rubber seals. Again look at the crank. They are complicated to install thats why no one does them . Watch the attached , it me help.

 
Auto Transport Service
Back
Top