C-Class - Wheelnuts Sheared - Simon Collier
I've just had 2 tyres fitted to my old C-Class today. The mobile fitters were using hand-wrenches only, but on undoing the wheelnuts one of them sheared. They called me over and I agreed for them to proceed. A 2nd sheared. Doing the other front wheel, 1 sheared and we gave up (one nut wouldn't budge and as it was next to the sheared nut we gave up).

I assume the problem is that the nuts were overtightened (at least one wheel is down to a certain national tyre company, who used an air-gun). No doubt I have no call-back on them as they had the car weeks ago.

Planning to limp home on my 3 wheelnuts, I've booked the car into my local garage, who I assume will have some way of getting the studs out. They have suggested that if the nuts were over-tightened that much there's a good chance I'll need new hubs and that'll cost me a fortune. Is this right? I was figuring on a couple of hours labour...

Am I 'safe' to drive home with 2 of 5 studs broken on 1 wheel (broken studs are opposite, not adjacent). It's 70 miles to get home, mix of Motorway and B roads. RAC?
C-Class - Wheelnuts Sheared - RichardW
You can't shear a wheel 'nut' - but that's a pedantic by note. Does it have studs in the hubs (nuts to attach the wheels) or holes in the hubs? The first might be easy enough to knock the studs out, the later will probably have ruined the thread in the hub, and new ones will be called for. I doubt it will be cheap.

"Am I 'safe' to drive home with 2 of 5 studs broken on 1 wheel (broken studs are opposite, not adjacent). It's 70 miles to get home, mix of Motorway and B roads. RAC?"

I might risk 3 or 5 miles, but 70 including m-way? Definitely not!
--
RichardW

Is it illogical? It must be Citroen....
C-Class - Wheelnuts Sheared - Bill Payer
The mobile fitters were using hand-wrenches only, but on undoing
the wheelnuts one of them sheared.

This isn't unusual with 'hand-wrenches' an impact air-gun may well have undone them fine.
C-Class - Wheelnuts Sheared - LeePower
If the studs are replacable on there own without changing the hub what are the others ones on the same hub like?

Might be worth doing all 10 studs if you can for peace of mind.
C-Class - Wheelnuts Sheared - 659FBE
These are wheel bolts not nuts. MB use a special type of bolt which has an extension outboard of the tapered seat, carrying the hexagon. This equates to a necked-down portion of the bolt shank relative to the point of highest friction (the taper) so of course, they shear off. Shear bolts are made in exactly the same way.

This is a problem which causes much grief to the owners (don't blame the tyre fitters) and there was an excellent article about it in the MB Owners' club Gazette recently. I would strongly recommend that however much you like your wheels, you sacrifice them to resolve this problem. The poor owner featured in the article had the hubs drilled out from behind - fraught with problems and future trouble.

Another piece of cracking design from MB - the solution to this one is to fit bolts with a hand wrench only, with copper loaded anti-seize on the threads and the taper. This is contrary to instructions, but I've never had one come loose. Make absolutely sure they come out and go back in every year regardless.

659.
C-Class - Wheelnuts Sheared - Simon Collier
Indeed they are bolts not nuts. Sorry. The guys today suggested copper grease on the bolts.

Sacrifice my wheels? I have Steel wheels, not alloys (or do you mean sell the car...) Sounds like I may need new hubs then ;o( The car is old - T reg and at 150k, manual with cloth seats, it's not worth much. Looks like Eurocarparts or German and Swedish for the Hubs, if not the breakers...

Thanks for your responses
C-Class - Wheelnuts Sheared - 659FBE
Sorry, wheels in my vocabulary are a device for keeping a tyre the right distance from an axle, not a mode of transport. The poor MB customer in the article had expensive alloy wheels which he was wanting to keep at all costs, hence the butchery further in. Although it's a stupid, irritating problem, your solution is easy - use a hole saw to cut around the bolt location on the wheel, remove broken stub (as it says in all the best workshop manuals - you might have to carefully chisel away the wheel remnant) then get new wheels from a breaker.

659.
C-Class - Wheelnuts Sheared - elekie&a/c doctor
This is a common problem on C and E class models.MB no longer supply the bolts with the extended hex nut.The replacement bolts are normal length and are recessed into the wheel.
C-Class - Wheelnuts Sheared - 659FBE
MB Engineer now relegated to form 1 mechanical engineering course. I wonder what else they let him loose on?

659.
C-Class - Wheelnuts Sheared - M.M
Simon.

Old C-class to you but just the thing I'm considering for a next car. How have you got on with yours?

DW
 

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