Replacing the Fourth Main

IMG_6500The fourth Main (Ball cap) has leaked since I first installed the engine in our Model T Pickup fifteen years ago.  This year it has been washing the grease out and the U-joint has been thumping so I decided to replace it.  Fortunately I had a ball cap (4th main) laying around that had been babbitted and rough machined. It was too tight for the transmission tail shaft in the car but I had another driven plate with a shaft that was slightly more worn than the one in the car. After a little scraping with a pocket knife I was able to force the cap on to the shaft and lap it in with TimeSaver coIMG_6314mpound.  I got it big enough that with some effort I could get it on to the shaft in the car.  I added some TimeSaver and bolted it to the transmission and started the engine.  It very quickly got hot and smoked so I pulled it off and lapped some more.  Put it back on the engine and I ran it and again it smoked.  I let it go for a while thinking it would “burn in”. When I stopped the engine the cap was frozen to the shaft and it took some work to get it off.  The babbitt had heated up and smeared.  I scraped it and lapped it some more and it slipped right on.  Maybe I over did it. I added some stickly Lucas oil treatment to the shaft and bolted it on. It didn’t overheat when I ran the engine and it didn’t leak so I hope it works now. Gaskets were made and I was careful not to use too much RTV on the inner gasket.  Hopefully I added enough. Update: September 14th, 2014.  Completed the Fall Colours Tour just fine.  No thumping from the U-joint and only a minimal oil stain on the floor after the tour.IMG_6508

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