Installing the input shaft seal

[Baby]

Last night after work and a stop at the market I came home, threw a dozen eggs in a pot of water, set it on low boil, and spent the rest of the night reading, searching the Pelican forum for knowledge, and watching The Getaway, every so often pausing to ask myself, "What is that smell?" As such, if I can carve out some garage time this weekend (and I will), I want to make sure my head is in the game before I do something I'll have to undo later---namely, replace an oil-soaked clutch plate.

So, 1) with a 915 from an 83, do I need to drive the input shaft seal on with a piece of pipe, or can I insert it into the throwout bearing guide tube and push the assembly onto the shaft?

2) Is it best to use a light coating of moly between the seal and the guide tube, oil, something else?

3) Does the fork that grabs the throwout bearing get moly on the inside? Is it best to put moly on the tips where they contact the throwout bearing?

4) Does the inside of the bell housing need to be totally dry and oil-free, or should I spray some preservative like Gibbs or WD-40?

5) Does the outside of the guide tube (or inside of the throwout bearing) get moly or oil, or should it be dry?

[Eagledriver]

There is a thread obove on this that shows a picture of the guide tube and seal. It will help you visualize the installation. The seal goes in from the "inside" (differential side). It goes into a tapered section of the guide tube. You need to drive it in with a piece of pipe being careful to only drive it to the end of the tapered part (use the depth of the old seal as a guide). Then install the guide tube being careful to not damage the seal. I put tape on the input shaft splines to prevent damage. Don't know the definitive answers to your other questions but here are my thoughts. The inside of the bell housing should be dry. The clutch fork should get a little grease on the fingers. The guide tube should get a little grease on it. I've used moly grease before but when it dried out it got sticky and I felt it did more harm than good. I now use synthetic wheel bearing grease. Be sparing with the grease, you don't want it contaminating the clutch.

-Andy

[yelcab1]

So what is that smell ?

[Baby]

It's the light, sulfuric smell of onset senility! All was not lost. I threw the eggs into the field across the street for the raccoons.

Thanks for the info, Andy. Turns out the seal just slid right onto the fat part of the shaft with almost no finger pressure. Considering how tightly the set I'm replacing fits together, I can't imagine the new seal got pressed tightly enough into the guide tube when that went on. Maybe the fit tightens with age?

[Baby]

Some pics, for anyone who searches this topic in the future.

Using a piece of pvc to drive the input shaft seal into the transmission side of the guide tube.



The seal in place.



I smeared the outer o-ring in this 22.00/liter oil I had sitting around, NOT in BP. Hope the whole thing doesn't blow up!

[RoninLB]

Originally Posted by Baby

So, 1) with a 915 from an 83, do I need to drive the input shaft seal on with a piece of pipe, or can I insert it into the throwout bearing guide tube and push the assembly onto the shaft?

the 1983 seal is an "outside" install... btdt
i used 10w dino for a lube
mine ate a new install with syn after 100 miles





915 Transmission Nightmare

Originally Posted by Grady Clay

crop
Starting with the 1976 model, the seal was changed to be inside a separate clutch release (TO) bearing guide tube.
This system is carried through the 911SC and 911Carrera.


© 1976 Dr. ing. h.c.F. Porsche A.G.


© 1976 Dr. ing. h.c.F. Porsche A.G.

The change in guide tube and seal occurred with the change to the electronic speedometer.
crop

Best,
Grady

[mikedsilva]

Originally Posted by RoninLB

the 1983 seal is an "outside" install... btdt
i used 10w dino for a lube
mine ate a new install with syn after 100 miles





915 Transmission Nightmare

This is an interesting topic: I have little experience but I just went to change the seal on my 915 from a 3.2 carrera.
I bought a replacement guide tube and a new seal.
When I removed the old tube, I damaged it.. I don't know why these things are so difficult to remove?

Anyhow, my question at this stage is the difference between the guide tubes for an SC vs a 3.2.

When I ordered the guide tube, I used a part number from a SC assuming they were the same. However, it appears that the seal location is different on the 2 tubes.
When I removed the old tube, the seal was right at the base, nice and snug.

But with my new tube, (SC part number), the new oil seal is VERY loose when installed at the bottom, and is in fact designed to be installed approx 10mm into the tube.. there is in fact a raised section which gives a nice interference fit for the seal.

So it looks like I need to buy a new guide tube with the 3.2 part number.. I've listed the 2 part numbers below.
SC 915 116 087 03
3.2 915 116 087 04

Or have I made a mistake?