Classic/Antique Car Repair: rear mian seal 1954 Mercury, wire mesh tube, rtv sealant

Question
I have a 1954 mercury with a ohv v8 cid around 252.My question is how to relace the rear main rope seal.I been told there is a tool that will alow replacement without pulling the trans,but I don't see how.I think they mean without removing the crank.Any info you can give is appreciated.
               Thanks,
                Jim Riley

Answer
There is such a tool, it is made on the principle of the old "Chinese Finger Torture" toy, which was basically a wire mesh tube, constructed so that when you pull on it, it constricts and grabs whatever is inside it.   

You do have to loosen all the main bearings to drop the crank slightly (just a few thousandths), and of course take off the rear main bearing cap.  Then you dig out the upper part of old seal anyway you can, with small tools, being careful not to scar the crank on the sealing surface.   Then push the tool around from the driver's side of the car until you can see the business end of the tool.  

Insert the new seal end into the tool and pull it up into the block with the tool.  Coat it with vaseline to make it slide easier, and bring it around until you can get the tool off it, then push it back into proper position and trim it if necessary.  

Of course putting the lower half into the bearing cap is easy.  Trim it, put some RTV sealant on the ends, and bolt everything back up.  Take baby steps here, just go a 1/4 turn or so on each of the 10 main bearing bolts until you feel the caps bottom out, then get out your torque wrench and slowly take up the torque to the right spec.

This is not the best way to do this job, and you might be disappointed in the results, but it should at least improve the leakage, and you may get a few more miles out of the engine before you have to remove it for a complete overhaul.

This process does put some added stress on the front seal of the transmission, but if you only drop the main caps one or two turns, it might not cause seepage from the transmission - if the front seal is supple enough.

Another trick is to just replace the lower half of the seal, and when you trim it leave it a tiny bit long, thus pushing up on the old upper portion enough to swell it microscopically.  This process requires only dropping the rear main cap, nothing else major, and doesn't put any stress on the transmission front seal at all.  You can always try this first - maybe the improvement will be enough to satisfy you.

Good luck!

Dick