O-ring for clutch release guide tube
 

replacing clutch parts on 6 spd trans. This O-ring is ~56mm and the guide tube is only ~41mm... clearly a mis-match. Pelican had no explanation. JFP..HELP http://986forum.com/forums/uploads02...1595342298.jpg
http://986forum.com/forums/uploads02...1595342380.jpg

The diagram you show looks different than your picture of where the o-ring placement should be. Are you showing the throw-out bearing guide tube with the o ring? The part # you stated is the o ring for the guide sleeve which is part # 99611608701. I think that's where your problem is.

Thanks 1Porsche...
Note your number is #7 in the diagram and the list. The diagram shows the O-ring is between the inside surface of that guide tube and the outer surface of the input shaft seal. My picture has the O-ring on the input shaft next to the shaft seal consistent with the diagram.

Here is a shot of the same O-ring on the inside surface of the guide tube I removed from my trans. My new guide tube is identical to my old one.

http://986forum.com/forums/uploads02...1595352285.jpg

Bootleg,
Take your old guide tube to a Napa auto parts store.
A counter parts person should be able to fix you up with the right size O-Ring.

there is no O-ring
 

It's actually easier than even that...Turns out that O-Ring is for the 5 speed. The 6 speed has no O-Ring which explains why I found none during my disassembly.

The old automotive diagnostic adage rings true= simplest things first.
Glad you worked it out.;)