Printable Version of Topic

Posted by: mrhurtalot May 7 2008, 09:15 PM

(EDIT) heres a link to the post with pics.. http://www.914world.com/bbs2/index.php?showtopic=83727&st=20#




my teener was out of commission since about october until two weeks ago, i finally got the cv fixed and reshaped the shift rod and several other little things.

man, it was awesome, for two weeks the weather here was perfect, i had the top off, just cruising about. looking like a BAMF.

but today, i pull out of my garage, drive about 3 blocks down my street, stop at the stop sign.

I start to go, when suddenly BAM!

the exact same thing happens.

the cv bolts shear off. car stops. and i go off.

so, ive probably got a bent cv joint. and a bent shift rod again.


can someone please explain. ive only got a 2.0. nothing fancy. this shouldnt be happening. unless its an undocumented feature of some sort.

Posted by: SirAndy May 7 2008, 09:21 PM

do you have the two pins that are supposed to lock the CVs and stubs together?

if you only have the 4 bolts but not the two pins, you're asking for trouble ...
Andy

Posted by: mrhurtalot May 7 2008, 09:30 PM

to my knowledge, yes, there are the spiral pins. i had that thought earlier, but pushing a car uphill for like 3 blocks generally makes one very tired and reluctant to slide under a car and check.

but i see no reason as to why they would suddenly be gone.

Posted by: SirAndy May 7 2008, 09:33 PM

with the pins in place, they *only* way you can shear off the bolts is if all the bolts came lose. there's no other way (well, maybe if you're pushing 1000 HP) ...

did you use NEW schnorr washers for the bolts? did you use the correct torque? did you make sure the thread was clean and not gunked up before you torqued down the bolts? new gaskets?
Andy

PS:

Posted by: r_towle May 7 2008, 09:38 PM

Gaskets...
I had simliar issues till I actually looked at the book and found a gasket in there....if you dont have it the bolts will feel tight, the the CV joint is never crushing the gasket so the bolts get loose.

Pull out the bolts, drill holes in them like Dr Evil does (or buy his) and use wire through the heads, new washers and new gaskets.
Rich

Posted by: mrhurtalot May 7 2008, 10:07 PM

will get pics tomorrow.

new gasket was in place. new bolts. yes washers.

again. let me emphasize that the car has been driven for less than two weeks after all repairs were complete. i seriously doubt that the bolts just came loose.


bleeh thanks for the fast responses guys.

ive got a fun day lined up tomorrow.

Posted by: Phoenix 914-6GT May 7 2008, 10:13 PM

You still didn't say if you have the studs in there or not.

Posted by: r_towle May 7 2008, 10:15 PM

Rich

Posted by: Gint May 7 2008, 10:16 PM

You did say...

Did they shear off, fall off, what? Have a look at it and get some pics.


Look at the bright side. It beats swapping out a transaxle for the second time in a week.

Posted by: SGB May 7 2008, 10:29 PM

I don't have spiral pins. I have little protuding cylindrical stubs, Maybe 8mm dia by 4mm tall.

I think something is wrong there, and has been from the start.

Those pins -er, I mean stubs- stick in pretty far...

Posted by: Phoenix 914-6GT May 7 2008, 10:36 PM

Posted by: mrhurtalot May 8 2008, 12:12 AM

by spiral pins, i meant the stubs. just to clarificate that.

Posted by: McMark May 8 2008, 12:15 AM

They sheared off????

If the pins are in place, and the bolts sheared off (not unscrewed) then perhaps they were over-tightened to the point where they were just waiting to break.

If the bolts did unscrew then use Dr. Evil's drilled bolts. And always clean the grease out of the bolt holes and threads with Q-Tips and brake cleaner. The less grease in the threads, the less chance it will unscrew itself.

Posted by: jd74914 May 8 2008, 12:46 AM

I would think that the threads would strip or be pulled off before you could force a bolt to shear.

If you had the pins they must have been loose?

Posted by: akellym May 8 2008, 06:20 AM

Don’t use gaskets!! They will compress over time. Just use silicon to seal it. Loctite will keep your bolts from coming loose.

Posted by: SGB May 8 2008, 07:05 AM

Evil safety wired bolts are cheap insurance.

Posted by: r_towle May 8 2008, 07:38 AM

I respectfully disagree.
If no gasket is used the CV joint does not fit correctly

Rich

Posted by: Racer Chris May 8 2008, 08:08 AM

I disagree with both of you.
The gasket does not affect the alignment/fit of the cv to the flange. What it does is prevent grease from slinging all over the place. A bead of silicone will not stay put for long. The centrifugal force will make it come off. At least on a track car thats what happens.

Posted by: Mark Henry May 8 2008, 08:15 AM

The spiral pins are fine, Porsche use both spiral and solid over the years.

Posted by: ericread May 8 2008, 09:41 AM

That's some amazing torque that would cause four bolts to shear off! I can't wait to the the pictures...

Posted by: PRS914-6 May 8 2008, 09:43 AM

I hate silicon and rarely use it. Yes, the gaskets keep the grease in and dirt out. Period. What I have seen is gaskets made too thick. You tighten the bolts and the gasket compresses but not allowing the metal on the cv and flange to touch. As time goes on, the gaskets compress and wear and what you have left is a loose set of bolts that come out and\or shear.

I quit using gaskets a long time ago and instead use Permatex Anaerobic Gasket Maker between the two actual faces (not in the gasket area)

The two surfaces must be perfectly clean before using the Gasket Maker. I also use lock tite on the bolt threads. The holes and threads have to be clean too. I have done this on both 911 and 914. No leaks of grease and no loose or sheared bolts.

Posted by: URY914 May 8 2008, 09:53 AM

I find it had to believe the bolts sheared off. I've never had this happen and my car had some pretty good power and hot slicks.

Pictures of the bolts?

Posted by: mrhurtalot May 8 2008, 10:23 AM

getting pics now. got my all black suit on, formerly all white..

BRB!

Posted by: Eric_Shea May 8 2008, 10:27 AM

New Schnorr washers?

Everything cleaned properly?

Proper gasket?

Torqued Properly?

Re-Checked the torque after driving?

There must have been a missed step in there somewhere.

Posted by: mrhurtalot May 8 2008, 10:52 AM

oh, there was a missed step.... pics uploading now..

there she blew.



looks mildly bent. bleh..



wtf is this... thanks dad for using the wrong bolts.. (you cant see, but its an allen head bolt, and its a little bit shorter than the RIGHT ones.)




OHH AND WTF ARE THESE DOING IN A DRAWER?




... dad--> <--me.


so what im guessing happened,

my dad calls a buddy, they decide to fix the axle while im tearing my hair out doing finals at school. awesome, i really appreciate it, until they decide to dismantle a perfect "new" cv, and put an old outer ring back on the axle, WITHOUT THE PINS IN IT.


so... when i see the axles reassembled, and in good working order, im not going to take it back apart to check the stubs... i fix everything else and go on my merry way.


this will be the last time i allow him to work on the car without my supervision.

between this, and the lug nuts he somehow stripped AND crossthreaded... i just dont understand!


but this should be an easy fix. just gotta find a torch to reshape the rod with.

Posted by: ericread May 8 2008, 11:14 AM

Thanks for the pics - it all makes sense now.

Posted by: URY914 May 8 2008, 12:42 PM

How about the threads in the tranny mounting flange?

Posted by: SirAndy May 8 2008, 01:02 PM

make *sure* those threads aren't stripped by now ...
Andy

Posted by: mrhurtalot May 8 2008, 02:29 PM

will check them, but i do have a backup flange. always prepared for the worst..

Posted by: MoveQik May 8 2008, 03:12 PM

May I suggest the safety wire from the Dr while you are in there.