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Gene, can you do this replacement with the engine in the car?
Jerry - yes you can but it is not easy. You also have to remove the transmission so you can drop the crankshaft down enough to slip the upper rope seal in. Trying to place the upper seal with only the rear main cap removed does not provide enough clearance to get the new seal around. Tried the Chinese finger but it was too big to pull through the pocket and the resistance elongated the rope confounding the objective. In the end it was heavy fishing line that worked best. I failed here the first time because of this, but overall I think I replaced the rear main 4 times while trying to get it all just right - each time learning a little something new. I used some heavy fishing line and a "blood knot" to pull the upper seal through the pocket, then I used the cut drum stick to push the ends in as much as possible, then torqued the crank bearing caps back up to spec, then finally trimmed the upper rope flush with the block face where the bearing cap connects. You can't leave a little tail on the rope seal hoping it will compress because it mashes up and fouls seating of the bearing cap. It has to all be pretty precise. I've attached a few more photos helping show what finally worked for me.
If you use the neopene seal he was refering to the instalation of the top seal is very easy to slip in place and all these operations are not necessary.
If you use the neopene seal he was refering to the instalation of the top seal is very easy to slip in place and all these operations are not necessary.
Gene that presupposes that you have a post '55 engine which I do not, and, all of the GMC light duty engines up to '59 (and Pontiac) used this rope seal and cannot use the neoprene. Gene you have the neoprene seal in your motor now? You speak as if you've done this and I'd love to see some photos of what you did to yours.
The way Oldsmobile suggested to replace the rear main rope seal in their last V-8 engines was to use a blunt tool (and small hammer) to compress the upper rope seal and cut of a short piece of the lower seal and stuff it into the gap Then replace the lower seal.
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Although we can read endless comments on main seals & how to seal them along with convoluted & complicated B.S. procedures ... { by novices that have never actually installed them }.
There is no need to make this any more complicated than it is....
Gene is truly an old school mechanic ....I have been using this "stuff & fill technique" for 40 years now & it works great with minimum leaks.
