rear main seal help

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63dartman

63dartman

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Anyone have any tips for rear main seal replacement? I'm picking one up later and installing it tonight or tomorrow. Do I need to coat both pieces with rtv or just where it joins? Is there a "trick to gettting the old one out?
 
Assuming this is a small block, and you want to install it in the car ?

The seal is split in two halves, one goes in the block, the other in the main cap. Getting the old one out of the block could be a bugger.

If this an old engine assembly the old seal might be a rope type. New seals are neoprene, they work interchange-ably.

Check at your autoparts store for a tool that looks like a T handle with a sheet metal screw threaded end on it. You thread the tool into the end of the seal in the block and pull it out carefully while pushing from the other side with a blunt piece of hardwood dowel, being mindful of the nearby journal. You may find it helpful to have the engine rotated the same direction while you are pulling the seal out. If its really stuck you may want to loosen the other main caps so the crank hangs down a little to get better movement and access to the groove.

Clean the groove in the crank and cap as best you can using solvents.

For sealant - what I found works well, is copper silicone sealant (hi temp stuff), coat the new seal's backside and also with a blob on the leading edge and install it in the block by pushing it in by hand. Leave it offset from the parting line of the block a quarter of an inch or so, make sure the lip of the seal points towards the inside of the engine as well. Rotate the crank and wipe the excess silicone off the knurled portion of the crank. You dont want loose strands of silicone floating around in the oil sump. They will clog the oil pump pickup.

Similar procedure on the cap portion, put a small dab of sealant on the mating surfaces of the two seals where they touch each other. Install the cap and torque it to spec. Wait 24 hrs before running the motor following the installation. Silicone needs at least 24 hours to set up.

Good luck !!
 
You know I should have asked this question when I was rebuilding my last small block. The book I was using as a guide said I should use RTV at the joining ends of the 2 rubber seals, but the gasket kit said NOT to use RTV. So I installed the seal not using RTV at the joining ends - it's leaked ever since. So as far as using RTV, I recommend using it in the channels around the seal AND the mating ends of the seals. Either way, I'm doing some mods now with the engine out of the car, so I'll just fix it this time around.
 
Thanks for the help, that was the big mystery for me. The package says no rtv at the mating surface. I think I will go with you guys and put rtv on the back sides and at the surface. Thanks again!!

The old one actually came out with little drama involved. I just ruined the first one by trying to force the top half and shaved the folded lip seal off of a portion of the seal:( Back to NAPA for another......
 
Thanks for all the help. I installed the seal as you guys suggested and it is holding up for now. (no leaks). I want to thank 66dartGT and Danmc77 for the help. 66dart your post helped a bunch. Thanks for taking the time to post such a long post.
 

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