(pics) 915 Bell housing mess - what to do?

[elflamo]

Hi all,

the bell housing on my 1972 915 tranny doesn't look good.

- lots of little hard pieces of what seems to be disintegrated rubber: what could this have been?
- loads of oily crap, however, not on the clutch. Doesn't smell like tranny oil and the flywheel seal needs replacement for sure. So assume the oil comes from the flywheel seal leaking. Just don't understanding why the entire bell housing is covered in this crud. The PO had a new clutch etc. fitted, so maybe that's why it's clean.
- Upon cleaning the Bellhousing I found a crack both in the inside and outside of the bottom left mounting point. Can this be welded?
- Furthermore, I found some strange wear grooves of whích I assume these shouldn't be there. I do recall that a PO had broken the engine crankshaft, maybe that has something to do with it.
- the clutch release fork: is it supposed to have vertical play of about 0.5 inch?


Question is: as this is the 1972 915 bellhouding with the annoying input shaft replacement issue, is it worth repairing this bell housing or am I to find a new bell housing post-1972?

Look forward to your ideas.

Thanks

Dennis

[euro911sc]

Looks like something disintigrated in there for sure and when you mentioned the PO broke a crank then that makes sense. Probably a mix of oil, water, and clutch dust with bits and pieces of clutch disc mixed in for good measure. You did not get to see the clutch before it was changed Probably a mess and they didn't do a good cleaning.

The bell housing can be welded. Probably even with out disassembly. But if you can find a cheap replacement it might be worth your trouble to take it all apart and use a newer part. If you are planning on a rebuild anyway then, obviously, send it all out to get hot tanked and cleaned up. Just make sure they don't use some chemical not appropriate for your case material.

The grooves are not an issue.

-Michael

[tctnd]

'72 tranny is magnesium. Welding can only be done by a qualified person with the right equipment and would definitely require disassembly. A replacement might be a better idea.
regards,
Phil

[Peter Zimmermann]

Replace it, Dennis. Then you can get rid of the stupid internal main shaft seal at the same time. Obviously, there will be costs involved in setting up the diff in a replacement housing, but in the long run it'll be worth it. You can also explore the possibility of up-dating the trans to a later model, but if you use a '76 or later unit you will have to also replace the speedo, and wire it. You will also experience a performance change if you switch to an 8:31 ring & pinion ('75>). Lot's of choices, unfortunately not many really good ones!

[yelcab1]

After I got rid of my 915 aluminum housing for half a song, everybody wants one !!! Darn.

[elflamo]

thanks for the replies guys. I've been told that just changing the bellhousing could cause bearing issues, as the various case parts have been 'line drilled' (I guess drilled as one piece).

I guess my first option is to try and find a rebuild post 1972 tranny and trade in this one.

Second best option is to get the crack welded and get the tranny rebuild including the removable input shaft tube.

I guess it is not easily possible to get my mech speedo to work with a wired trans?

Thanks

Dennis

[elflamo]

By the way, is there an easy way to check whether the input shaft is bend? Would one see wobbling of the shaft within the guiding tube?

I'm asking, as someone give me some input that the grooves might be related to a bend input shaft.

?

Dennis

[911pcars]

Converting to an electronic speedo drive is the least costly in your situation. All you need is a compatible speedometer.

Going inside the gearbox could be a slippery slope, especially if everything is okay now (notwithstanding the main shaft seal). I'd clean the oil/debris mess and repair the crack first, then see where you are.

Sherwood

[Fishcop]

If you elect to keep and repair your bellhousing, I found this option at Wevo a good fix for the 72 guide tube issue http://www.wevo.com/Products/TransmissionProducts/WevoTransmissionProducts-RaceCaseGuideTube.htm You could probably have the crack welded at the same time.

[Elombard]

Hmm.

I wonder if a qualified re-builder could have that welded while they were building it (Fairbanks or JW).

You can probably get a decent early 915 for $1500 or a core for $900 and have it built. Yours is probably worth $600 as a core??

OK let me go on a limb....if it shifts Ok what if you just put it back in for a few years??? I wonder if a home bent washer to spread the load out would be safe for a few years? I nthe mean time you could search for a new one or whatever....

I am guessing the crack came from some one over tightening it when it was not ligned up right or something, not sure it sees a lot of load along that crack. I dont know its your noggin.

[mike55]

I'm pretty sure I have a good 915/61 mag bellhousing/main case available for sale if you need one. Shoot me an email and I'll send pics if interested.

Mike