rear main bearing leak

N

ntqlvr

Member
Hi, just bought a coupe, old restoration which has a rear main leak. I checked out all the possibilities of overpressurized case etc. So I pulled the pan and rear main bearing. From looking at the inside the engine was rebuilt and rebabbited not too long ago. They also had installed a seal...two piece rope type, and looks like the slinger was turned down to do it. I'm thinking that maybe there's too much clearance on the bearing. Also is this kind of seal any good? It sure was leaking. I can replace the bottom of it but the top would be difficult. Any suggestions? If I get the clearance on the bearing to .001 will that do it?
 
I had the same problem and consulted Model A engine builder Dennis Peranio in Denton Tx. He told me to revove one shim and reinstalled the rear journal and torqued to specs. Then turned the engine with the hand crank. I repeated the process alternating shim removal from side to side until I got to the point i couldnt turn the engine I reinstalled the last shim I removed and buttoned everything up. My Exxon Valdez oil leak was gone and the car runs great!
 
After setting the correct clearance, it might still leak to some degree as most replacements for the slinger do not work very satisfactorily. There were two sizes of oil return pipes on the rear main. If you have the larger one it will help. You can probably replace the rope seal with a Burtz seal or one from a 350 chevy, but the crank must be the correct size and you will definitely have to pull the engine to do it. If the crank was ground too small for those rubber seals, you will have to live with whatever oil gets past the rope seal.
 
If you re shim the rear main bearing it will work for a wile and then start to leak agin ( good for about 1,000 to 2,000 miles and then it will start to leak agin. If you pull the engine and remove the crank you can have the slinger turned down the rest of the way and install a berts seal ( Read the derections it is important. ) This is the only way to get you engine to stop leaking. I have had to do this to a number of engines for people and it works like a charm. Email me if you have any questions.
vinepro@comcast.net
 
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