Late 915 input shaft seal doesn't fit...?

[cashflyer]

I'm going to borrow tref's picture for this question.



I have a later 915 with the removable guide tube. The seal I removed from the tube is similar to the middle seal pictured. It had a generous amount of silicone around the outside mating surface.

Now that I attempt to reinstall the new seal, I find that apparently the silicone was "glueing" the seal into place. I figure this because the new seal just drops into the recess with no real sealing value at all.

WTF? Was the wrong seal in my seal kit?

If this is a common problem, is there a common solution?
Silicone again??

And before anyone asks... the large diameter seal on the right is way to big to fit in the tube unless I start machining out some metal.

[Joe V]

I'm rebuilding my late 915 out of my '84 Carrera. Having the same issue with my guide tube seal.
The new seal seems to be too small for the new guide tube.

Any suggestions are appreciated.

Regards,

[Porsche_monkey]

Subscribed. Waiting for Peter Z. to explain. I've never had this issue....

I recall the bore having two diameters. Are you sure the seal is being placed at the proper depth?

[john walker's workshop]

later seals sit about 11mm deeper than earlier seals. just push it through farther until the lip is flush with the inner end of the tube. remove the tube to do it.

[Joe V]

Monkey,

That's my issue entirely. At the rear of the guide tube (transmission side) the opening is slightly smaller in diameter than towards the engine side. The new tube has a only one step biased toward the rear of the tube, where the old tube has the step slightly forward of the rear. Make sense?

[Porsche_monkey]

I did one last week. I think I just pushed it in from the engine side, i.e. the long way...and I think it was tight all the way, but I am not at all sure about that.

[Joe V]

Thank you gentlemen!
May I ask about the throw out bearing? It seems "loose" once it was tightened down on the flywheel. Is this normal?

[john walker's workshop]

it can be moved radially, yes.

[Joe V]

JW,

You rock. Thank you so much.

[al lkosmal]

took me two tries to figure that out.

[Joe V]

I pushed (tapped, actually) the seal in with slightly smaller socket than the guide tube until just about bottomed out. I then wrapped the I/S with genuine Porsche electrical tape (I accept no substitutes, and at $32 a roll, rarely use it (lol)) and slid that puppy home. As a precaution I put a little grey RTV at the base of the guide tube (not on the o-ring, but where the tube "shoulder" meets the tranny "shoulder"). Put a drop of blue Loctite on the screws and snugged them down. We are almost there with the reinstall. Tranny is ready to mate up with the powerplant, but I've got a couple of pieces out cleanup. So this saga will hopefully conclude in a couple more weeks, since I'm heading to Orlando today for a 3 day photo shoot...

Thanks again for the advice and help. Couldn't have gotten here without the help of this outstanding forum.

[Eagledriver]

I'm reviving this thread because I have a similar issue and want to make sure the new seal will work before removing the old seal.

I have a 72 transmission with the unremovable guide tube. The new seal is loose in either end of the tube. I haven't removed the old seal yet. Does the tube have a smaller diameter in the middle where the seal goes? How does one decide how far to put the seal in?

-Andy

[christiandk]

Anyone on this problem - the seal seems too small in diameter for the new tube. I figure if I try to push the seal over the elevated part (lip) of the tube I will tear the seal.

The seal will not seal the tube when it is pushed up to the lip.

I have double checked and I am pretty sure I got the right tube and seal kit 087 03 /327 40

Thanks.