Replace Non-leaking RMS?
 

I'm undecided and looking for some thoughts.

I'm in the process of replacing the IMS bearing on my 01S. It's got a little over 30,000 miles on it and I'm doing the IMS for peace of mind. Before pulling the car apart I was certain I would be replacing the RMS as well and purchased the updated one.

The original RMS is still in place. When I pulled off the flywheel there was no evidence of any oil leaking at all. If it weren't for a little bit of clutch dust, I could have eaten off of it!

That's where my concern arises. I'll drive the car less than 2k a year. I'm thinking that I should let that sleeping dog lie. I'm concerned that I'm more likely to cause a leak than to prevent one. Any thoughts?

When I had my IMSB done by a shop I had them also replace the RMS and the clutch while they were in there. The car only had 25k miles on it and neither the RMS or clutch had any issue, but I thought, while it was all torn apart, why not freshen up the area so it would all be set for 50k miles before needing service again. My plan is to have it all replaced again at 75k miles when the ceramic IMS bearing needs to be replaced. Hopefully, the other parts will last that long and it will all be on the same schedule for maintenance in the future.

The best tech info on this subject is on Renntech by JFP. Elsewhere there is lots of well intentioned noise. Ahsai posted some excellent photos that confirm the advice and experience of JFP.
The very short incomplete version is:
1.to be successful, RMS replacement requires scrupulous attention to tedious.obscure details -per most M96 issues!
2.use the 997 upgraded part
3.use the correct tool -diy construction O.K.
4.set to the correct depth & slightly deeper than any groove worn in the c/s.
The "slap it in & get 'er done guys" need not apply. Better to leave the old one in place for them.

The justification for replacing the RMS is that the rubber is now 15 years old and has probably lost much of its elasticity making it a prime suspect for a possible leak in the future.

But as you mention, any type of invasive procedure creates the risk of introducing or creating a problem where there was none previously.

If it were me, I'd replace it while following Gelbster's advice regarding JFP's recommended best practices.

FWIW, I had my IMSB replaced at 42k miles on my '03S in 2012. The RMS was bone dry, and consulting with my Indie P car specialist doing the work we decided to leave it alone. At 48k miles the RMS started leaking, so the transmission came back out and I got a new RMS. I am now at 65k miles and it is still dry. I don't know if removing and replacing the flywheel puts any new forces on the end of the crank or the RMS which could cause it to start leaking, but mine did start to leak 6,000 miles and a year after the IMSB was replaced. In the future, like when I need a new clutch, and if I replace the IMSB again, I may just do the RMS again too.

Even though my newly installed 997 seal blew out during a track day I would still go ahead and change it as advised herein

I'm a careful guy when I do this kind of work but I'm not so confident about my skills. I've done an RMS in the past but not on a Porsche and the "floating" seal that isn't seated against anything makes me nervous. Great advice here though. I'll try to make a tool and if that works out, I'll do the job.

The newest seals are much more durable than the old ones.They are however, very tedious to fit correctly.

Actually, the updated RMS seals are a PTFE material which was designed to correct the problems encountered with the original Viton seals.

I would not hesitate to replace your original Viton seal with the PTFE unit; they are inexpensive and do an excellent job. As mentioned, all surfaces must be scrupulously cleaned and you should not touch any of the new RMS surfaces without wearing latex or nitrile gloves as even finger prints can cause leaks. Do not use any type of sealant and be sure it is installed straight and to the correct depth.

Thank you for the advice. I'll keep things clean and if I mess the seal up putting it in I can always get another.