915 output shaft seal

Vincent 911 · 01-16-2008, 05:18 AM

I am done with engine rebuilt on my SC. I am currently working on front brakes, new Bilsteins, turbo tie rods.
I recently found a leak on the passsenger output shaft of my transmission. So I need to change it.

Here is my question: whats is the procedure to replace the 915 gear box output shaft seals?

Do I need to remove the big nut of the transmission shaft on the wheel side (I believe it requires a 36mm socket and a lot of torque)

I did not found any post which mentions the procedure to change this seal and I don't think it is in my 101 project.

Thank you

Grady Clay · 08:20 AM

Vincent,

No you don’t need to remove the 30 mm wrench size stub axle nut.

The procedure is:

In advance have six new M8 bolts, six new Schnorr washers, the CV joint gasket, a new seal and an installation tool (all available from our host).

Remove the six M8 Allen socket head bolts on the inboard CV joint. It is easy to ‘round out’ the hex so make sure the socket in the bolt is clean and your tool is perfect.

Separate the CV joint from the transmission axle flange. Be careful to not damage the mating surfaces. Just let the axle hang or wire it out of the way.

Remove the stretch bolt from thee center of the transmission axle flange. You can install two of the old bolts in adjacent holes and use a wrench to prevent the flange from turning.

The axle flange will now slide out of the transmission.

Confirm that your new seal is the same as the original.

Pry the old seal out taking care to not damage the seating surface in the casting.

Clean and inspect the sealing surface in the casting.

Using tool 9252, P 265c or equivalent, press (hammer) in the new seal. Make sure it stays square and the tool seats against the casting. Visually inspect that it is installed square.

Clean and inspect the transmission axle flange paying particular attention to the sealing surface. Do not use anything that will scratch the sealing surface.

Lightly grease the sealing surface of the flange. Oil the lip seal.

Reinstall the flange and tighten the stretch bolt to 26-30 Nm (18.8-21.7 ft-lbs).

Reattach the CV joint to the flange with a new gasket, new bolts and new Schnorr washers. Take care that you don’t get grease on the mating surfaces or on the bolt threads in the flange. Torque the M8 bolts to 33 ft-lbs.

After some driving, re-torque the CV joint bolts.

Check this thread:
http://forums.pelicanparts.com/showthread.php?t=222537

Best,
Grady

Vincent 911 · 01-16-2008, 07:14 AM

Thank you very much Grady. That's clear and well-detailed. It seems to be pretty much forward.

I will keep you updated.

Inniswhe · 01-17-2008, 05:35 PM

Grady,
Are you sure Pelican has thr insertion tool ? I can't seem to find it on the site ?

Grady Clay · 01-17-2008, 05:42 PM

No, that was an assumption on my part. Call Pelican Parts and ask.
It is a simple press tool. I have an original P-tool I can measure if you want to make one.

Best,
Grady

Thrlls · 01-17-2008, 06:04 PM

Quote:

Originally Posted by Grady Clay

No, that was an assumption on my part. Call Pelican Parts and ask.
It is a simple press tool. I have an original P-tool I can measure if you want to make one.

Best,
Grady

Grady -
Thank you for the great detail on the DIY output shaft seal!

Do you have a picture and the measurements for the seal installation tool?

My engine and transaxle is currently sitting on my garage floor, and I'm thinking I should probably do this now than later.

Thank you!

Grady Clay · 05:45 AM

Here is a crummy diagram (my coordination with the mouse still isn’t good). The critical surface is the
45.00 mm dia surface that the seal slides over. This (and the lead-in taper) needs to be finished as the
transmission axle flange where the seal runs. You don’t want the tool damaging the new seal.
The 2.0 mm dimension determines the axial position of the installed seal.
None of the other dimensions are critical.

In my diagram I show two lathe centers. This should be easy to make on a metal lathe;
three diameters and three faces plus one finished surface with taper.

The hollow center is necessary for clearing the threaded piece in the '65-'67 non-simplified differential.

Revision 2

I bought this tool from Porsche in 1968.
It could use some TLC to get rid of the old sealant.

Best,
Grady

Thrlls · 01-17-2008, 08:54 PM

Mahalo Grady!

You're better with a mouse than I am with a pencil!

Nice pics too!

Mitch Leland · Mitch Leland's Garage

Grady,

Why don't you want grease on the CV threads? I was thinking of anti-seize... Will that allow the alan bolts to back out or lose their torque? In my case I have 10mm alans.

Thanks,

Inniswhe · 01-18-2008, 03:19 AM

Thanks for the details on the press tool , greatly appreciated. I am doing the same repair so I will make one since I am a long way from a porsche repair shop or supplier (PEI Canada).

Grady Clay · 01-18-2008, 06:05 AM

Mitch,

Check the thread I linked above:

http://forums.pelicanparts.com/showthread.php?t=222537

NOTE: Diagram of P265c is revised above.

Best,
Grady

MBEngineering · 01-18-2008, 10:39 AM

HI ,
please check when changing the diff oil seal the depth it is fitted in to the case, as the tool Grady has only fits one 915 gear box case and there is 2 others to fit the seals at different depths in the diff side plate as the photos bellow.

the center tool is a modified P265C to fit the oil seal.

this is the 3.2 Carrera side plate (with oil pump).

this is a later SC side plate.

this is a std flush fitting seal.

regards mike

Inniswhe · 01-18-2008, 11:01 AM

I have an 84 Carrera with a 915. Do you guys know if the dimensions of grady's tools are correct and if not what is the dimension. I believe the only critical dimension is the depth from the face of the differential case. I expect the rest of the dimensions can be obtained from a new seal. I can check the depth of the old one before I remove it I suppose.

Thanks

Ross