DanG

I've had problems with my CV joint bolts backing themselves out (even after cleaning/locktiting/torquing) but the've never done this.

Today, under normal driving conditions, the drivers side outboard bolts gave way. Moderate accelleration from a stop, happend on a soft shift from 1st to 2nd. I'm guessing they might have sheared off one-by-one over the past year or two that I haven't messed with them and today the last one or two snapped off. Now I've got six broken bolts and 6 studs left in the wheel hub.

I'm going to try my best at removing the broken studs tomorrow, but I'm not sure where to get the right bolts. I'd like to go grade 8 if I can, does anyone know the thread count/diameter and overall bolt specifications off hand? Does anyone have a good source for these? McMaster Carr? Local fastener supplier? I think I'll replace all 24 of them at once, cause who knows how many others are snapped too.

Attached is a picture of the portion of the hub with the broken studs.

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Red Devil Racing

nine-44

I myself, would go with OE. The broken bolts should come out with little trouble, drill and easy-out them if the won't come out with a screwdriver. The locktight may be the bigger problem, maybe mild heat would help that?

DanG

wow, fast response, thanks.

I hadn't though of OE for them, I guess that is an option. Only problem is, I hate those darn 12 pt. bolts, thats one of the reasons I swapped them out. Went to an internal hex bolt. Should be capable of the required torque.

Here's another picture...

nine-44

Look at Audi or VW, they used some hex blots instead of the 12pt or cheesehead BS. I worked at a Porsche-Audi dealer for a while, they had both, just depends on what side of the parts department you were on. Good luck.

nine-44

I'm thinking maybe the A4 or S4 used the 6pt you want, look around, you'll find them in stock and pretty easily too.

DanG

Good idea, there's a Vdub dealer right down the street.

Thanks for the help Andy.

tasdevil

When you go to drill them, drill them from the back. Alot of the time the drill will screw them out quite easy.

DanG

good idea tas,

on a related note, are there supposed to be any kind of lockwashers or not? the threads seem rather loose, I can easily turn a bolt through the hole with my fingers. There is probably grease in the threads and it may be the wrong size bolts (remember I replaced them with hex heads). But I'm wondering if say a split or star lock washer would help or hurt me.

I do plan on cleaning the threads and using loctite.

Hans

Dan

Bolts are M8. Lenght to be taken from the ones you have.
The quality you require is 12.9 as a minimum.
8.8 will shear-off (as you must have noticed).
Allan head is available in that quality, but quality is not normally stamped in, so you have to watch the box they come from.
VW dealer is the best bet.
Loctite will disintegrate if heated so heat up.
either an torch, soldering iron or the hair drier can do the job. Just heat the stub.
TakeCare

tasdevil

I don't see a problem using lock washers, or in a bad case you can run a small drill Thur the head of the bolts. And then use wire to lock the bolts together, which will not allow them to work loose. I have had this problem before, and the wiring stop it . But washers and loctite will work fine, Don't forget to allow for the washers in your bolt length.

Julian Allen

Crossdrilling and safety wire will keep them tight, but driiling 12.9 material with a small (1/16) drill is tough and you'll break a few bits. 24 bolts means 48 holes (90 degrees apart).
The threads must be meticulously clean to maintain the torque: if you get any grease in there you won't get them to stay. When you buy a CV joint from the factory you get new bolts, so there's a hint about when you should replace the bolts.
This is one of the times using a torque wrench makes sense. Snap-on makes an extended triple square bit that clears the bellows of the rubber boot better than a 3/8 extension, tends to make the job easier.

DanG

Ok, everything went well today. I got 4 of the 6 free with only my fingers. The last two got some holes in the drill press and then came out without much trouble using an ez-out.

I picked up some bolts from a good VW shop in Pittsburgh for a few bucks.


Interesting note, when comparing the bolts I had in to the ones I got that were meant for the job, my old ones had a larger diameter unthreaded portion. Like the unthreaded portion was equal in diameter as the outside of the threads, the threads were probably cut. The "real" bolts appeared to have rolled threads, as their inner diameter was the same as the unthreaded portion. My guess is that the larger diameter bolts might have been in contact between the CV and the hub, right at the split. Thus it would be getting a much stronger "cutting force" compared to the smaller diameter bolts which only contact at the head and on the threads.

Thats a lot of words for CV bolts.

But thanks for the help guys. I cleaned the threads with solvent and used blue threadlocker, I'll check periodically to see that it holds.

Dan

Perry 951

I have made it a habit to check the bolts each oil change. I tossed the bolts on my fathers 911 when I was 17, and shortly after I bought my car, I was on the side of the road with the inner right bolts backed out.

Every now and then, I'll find one or 2 that are finger tight, and I'll snug them up when I get the chance.

sm

What's the torque spec on the bolts?

stoked944

The exact exact same thing has happened to me. In fact just the other day they were loose and i took them out put locktight on them and put em back in. Hopefully they will stay tight. For some reason i doubt it. I need to clean the threads out because they are greasy. I think thats the whole problem. Mine also have completely sheared off before too. I'll have to save this thread. It should be helpful in the future. Let me know how everything goes and if they stay tight.