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QUESTION: What is involved in replacing the rear seals? Do you have to pull the clutch?

Is it a major job?

Hi Joe, I'm not sure on the minutia of replacing the rear main seal, but if it is leaking and has soaked your clutch disc, it most certainly should be replaced anyway. Providing it's slippage hasn't translated to excessive heat and warpage to the pressure plate (and presuming it is in decent shape to begin with) one could cleanse it of any and all oil before putting it back in, but clutch discs are like brake shoes - once they're soaked in brake fluid, they are pretty much throwaways, or, in our world, good cores.... I also think the clutch would have to come out just to physically get AT the rear seal, and would GUESS, the flywheel may have to come off as well. Of course all those who've done this numerous times will weigh in and clarify, but I would consider it a 'major' job. Chris.

Thanks, Chris. As you may remember I washed the pressure plate in situ with brake cleaner after I found the primary source of the oil leak from the transmission lid and that has worked for months. I'm also getting oil on the garage floor again.
If I could figure out where the leak is coming from that's getting on the clutch, washing the clutch may work.

Several people have said Rear Main Seal, straight-8s are notorious for leaking there.

So I really need a definitive answer on what steps are essential to replace and make make a seal. Like:

1. Drop the oil pan
2. Remove the bearing cap
or whatever

I hope someone here knows. I couldn't find anything but the attached.

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You do not need to remove the clutch, you should remove the transmission. Remove the rear main bearing cap and fit the new graphited rope seal and form to shape with a suitable mandrel and trim as needed. Loosen all the remaining main bearing caps slightly but equally; remove the old upper part of the seal by some combination of pushing and pulling and use a "sneaky Pete" to draw the upper half of the new seal into place and trim. A small blob of gasket shellac at the juncture of the upper and lower seal ends is a good practice. Retighten and torque the bearing caps, install the wooden side seals in the rear bearing block.

Properly installed, these rope seals are quite effective and long-lasting, typically lasting the life of the motor. In addition to the Packard manuals, manuals like Motor's, Glenn's, and Chilton's all gave instructions on seal replacement, a common job at the time though not one I ever looked forward to. The Sneaky Pete (a/k/a Chinese Torture Toy) is in my experience pretty much essential to the job. It was typically sold as a rear main bearing oil seal installing tool.

You might pick up the phone and talk to Ross Miller, I suspect he's done this dozens of times and may have some tricks to simplify the job.

Thanks much, Dave. Per Chris' suggestion, if the tranny has to go, then I may as well replace the pressure plate. I'll search my manuals again. Much appreciated.

Packard had issues with some of the wood seals being too small and in 54 they also changed the wood to cork which was supposed to help get a better seal. That change was retroactive for the prior engines. If your seals are currently wood maybe finding a cork set would be a worthwhile change too.

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Thank you, Howard,
I will check with Olson or another gasket place for the cork one and also have them check the dimension of the wood ones. So there is a hard cap seal and a rear rope seal. I'll check th eparts book for the distinction. Thanks for raising awareness of this change.
Sick of drips,
Joe

Unless supplier packaging practices have changed, when you purchased a rear oil seal kit, the kit included both the two halves of the graphited rope crankshaft seal AND the two wooden or cork pieces which seal the sides of the lower rear main bearing cap. It was sold as a rear main bearing seal kit, also all the components were always part of a full gasket set.

Hi Joe,
I'm not sure if the seal on your car is the same as my 53 engine, but here is my experience.
I made a little "funnel" that made the job possible. It is a pain in the butt in general, however rewarding when the engine does not drip.
My seal really fell apart, so it was a lot more than a drip.
My project blog P38
Page 38 and 39 were my trials and tribulations with the rear main seal.
I tried first with an "old original type seal", and had no luck. Then I tried with a modern graphite seal and it worked. I think the newer seal is more flexible, which makes it easier to snake into the block.

Joe,

I read all through Tobs blog on his rear main seal replacement and got up to speed on the process. I did not realize that the seal was accessed from INSIDE the oil pan. From my very limited knowledge and experience on rear seals, I wanted to ask (probably at the risk of sounding stupid!) why the tranny should come out? It just rests in the pilot bearing recess of the flywheel and would rotate easily in neutral, to turn the crank, while feeding the new seal in to the cavity - what purpose would NOT having the transmission in place, serve?? (possibly crank end play?) Never having done a R.M.S. I presumed it would fit into a recess on the exterior of the block, behind the flywheel - thus my previous thoughts on removing the clutch. Once you do get the leak stopped, I'd sure still consider putting a new clutch disc in, as no matter how degreased you can get the surface of the old one with brake cleaner, if the sintered fibre is oil soaked, it could still give you trouble down the road with slippage and chatter. I learned that one the hard way and had to tear everything back down and redo it all with a new clutch. You'll be going through enough work here, you sure won't need that! Chris.