Front seals

3

37 truck

Senior Member
I got my 1940 flathead running following a complete rebuild, and everything has gone right except after about 50 miles the one piece front seal is leaking. When I slow or go to stop it leaves a stream of oil on the pavement. This is as the oil in the pan moves forward. We had put a reddi sleave on the pully shaft. Now I get to drop the pan and replace the seal. Should I go back to a two piece seal, or try another one piece seal? Thoughts? It is a PITA!
 
The seal was installed with the lip towards the interior of the engine. I pulled the pulley and found the seal looks ok, measures 1.50 with the crank being 1.3135 and the gap to the seal at .09375. My pulley has the spiral as part of it, not two piece, so I put a reddi sleave on it that measures 1.6345. It seems the seal should be fine. What I think is happening is oil is going under the seal and coming out, the trough that the seal sets in is large on the pan portion and deep in the center. I am going to try a sealer on the seal to pan, put it back together and give it a try. I will let you know.
 
The seal's the problem being far &way too big it has to&must be 1.312 (1.5/16),
Also the redi sleeve ID is also far&way too big it too has to&must be 1.312 (1.5/16),
1.500 is i.5-2 MM bigger than 1.312(1.5/16) (33.3375 MM), it'll be too loose on the shaft......,same with the redi sleeve at 1.6345.....
 
37 truck said:
The seal was installed with the lip towards the interior of the engine. I pulled the pulley and found the seal looks ok, measures 1.50 with the crank being 1.3135 and the gap to the seal at .09375. My pulley has the spiral as part of it, not two piece, so I put a reddi sleave on it that measures 1.6345. It seems the seal should be fine. What I think is happening is oil is going under the seal and coming out, the trough that the seal sets in is large on the pan portion and deep in the center. I am going to try a sealer on the seal to pan, put it back together and give it a try. I will let you know.
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And me? I'm thinking as long as you have this disassembled, install the proper two-piece rope seal and be done with this project.
 
I'd listen to "Kube". Years ago, I bought a one piece seal to use in an engine I was doing. After looking it over and doing a little research, I installed the original seal.
 
I have installed many 1 piece seals on my builds and have yet to have a problem, even with the stock spiral sleeve.
 
I had a leak on the new engine due to different sizes of the seal slit in the (US) pan versus the (french) timing cover. So I removed the pan and measured the differences. The slot was quite a bit wider and deeper in the pan than on the timing cover. I made a filling mold to the dimensions of the cover and put some JB-weld into the pans slot, followed by the mold. Let it cure overnight and next day I had the exact copy of the upper slit in the pan. Redrilled the drain hole and put a new rope seal in. Now there are no leaks at all, bone dry.
 
Well, I pulled the crank pully, and found the lip seal looked good, spent some time sealing around the seal, reassembled and restarted the engine. Didn't leak around the front seal at all, but an oil leak developed, or continued from the cotter pin hole in the flywheel pan area, leaking a thin pencil lead stream. This engine has a slinger in the back, so I'm at a loss. It didn't start leaking until I had about 50 miles on it. Guess I have to pull the engine next. That flow was with a warm engine at idle. Cover over oil pump to cam gear? Oil channel plug not tight?
 
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