How bad is one broken CV bolt?

[Rick Lee]

Just decided to retorque my CV bolts after reading some horror stories and found one spun freely. I tried to back it out and it came, but was shorter than the others and obviously broken off. I have to assume it's been this way for a very long time, as none of this stuff has been touched since April '05. I figure close to 8k miles ago. This is the 993. I don't have time now to deal with pulling the CV and drilling the bit out and all the others were tight. How bad is this?

[Rot 911]

You are going to die.

Seriously if you need to drive for awhile before you replace the bolt I would be checking the rest of them on a weekly basis.

[jevvy]

is it not worth just pulling al lthe other bolts and see if it will wind out with a punch or similar.

You may find the bit that is left in the stub axle will spin easily then you can just chuck a new bolt in and be 100% happy.

[David]

The broken piece should come out pretty easy if you have the time to remove the others and pull the CV out of the way.

[Jim Richards]

Originally posted by Kurt V
You are going to die.

+1

Just give me your 993 and your worries will be over.

[harold12750]

I am in the same boat 83sc , sheared all outboard bolts on drivers outboard cv, got all but one of the pieces out, 5 are working fine for me, I drove tentatively at first, but doesnt seem to be an issue at any speed or shift point (hi revs) plan to address in winter . five did come out fine so if I were you I would definitely try . good luck

[Nine9six]

Is this your daily driver? If yes then address the issue sooner rather than later. If not, take care of it in the winter when you wont miss driving it quite as much.
I'd go easier on the right foot till I got the problem corrected. No sense in adding undue force to a less than optimal CV joint.

[Grady Clay]

Ick,

Your 993 has six M10 CV joint bolts (8 mm Allen wrench) for each CV joint. I have never seen an M10 bolt broken other than when the joint connection had been loose. They won’t fail otherwise. I suspect even over-torqueing would show other symptoms. The spec max is 66 ft-lbs. I wouldn’t expect a failure even at 80 ft-lbs.

I would replace all the bolts (both sides) and Schnorr washers with new. You can (and should) do this one bolt at a time. This maintains the clamping force.

The one with the broken bolt may have to be disassembled. Great care should be taken to prevent grease contamination of the joint connection.


Good for you for checking. This is regular maintenance that every 911 should have. Congratulations.

BTW, Earlier 911s with M8 CV joint bolts have a much greater problem.

Best,
Grady

[Rick Lee]

Ok, update here. I lied. It was in my SC, but I wanted to see if I could fix it before the buyer arrived today. I went to the shop (ASG), bought new bolts, rushed home and took the inner CV flange off. Broken bit was below the edge of the output flange, so there was no using a vise grip to turn it out. It has to be drilled and my drill got nowhere fast on it. I installed the five new bolts, called the buyer who was en route but still two hrs. away. I told him I'd knock $200 off the price for that or pick up the tab if he had a pro fix it. I assured him that I had a good 5-8 DE's on there with that bolt like it was, so it was not an issue for getting the car home. I left him the one new bolt to match when he gets new bolts to fix it at home. He was very happy with the car and it's sold now.

[Zeke]

Hopefully he will attend to it and not shine it on.