Broken lug bolts on 1994 C220. Has anyone ever heard of this?
 

A good friend of mine called me and said three of his lug bolts broke off his rear wheel. He torqued them to spec when he put the wheels on. What would cause this? They are sheared off clean in the hub.

Is there any way to get these out or is it time for him to buy a new hub?

TIA,
Steve

Time to get a new torque wrench? Hard to see why three bolts would shear at the same time if they were correctly torqued.

If properly installed, it is only the loading created by the wheel that holds these bolts tight. With the wheel off and the load off the bolts, they should come out pretty easily, perhaps with an easyout, our use a punch to drive them round.

The threads may not have been clean when torqueing the bolts.

Corrosion/lack of thread lubricant?

use a reversed drill bit to get them out, that could work too.

xp

They were possibly already damaged due to previous overtorqueing by monkeys with impact wrenches. One more cycle and pooof.

Duke

Overtorqued bolts would show up with necking at fracture.

What is necking?

Boy & girl, in the backseat of a car ! :D

"Necking" in regard to bolts is the reduction in diameter
 

at the point of the break, caused by the stretch of the bolt when overstressed. Necking in the back seat of the car, on the other hand, often results in an _increase_ in the diameter of the midsection of one of the participants, some months later.

Ask your tool supplier for an Ultra-sonic bolt releasing tool kit, works like a jiffy every time!! It mounts to the wheel and uses sound waves to slowly deteriorate the corrosion around the lug threads, allowing you to remove the broken studs with a simple pair of pliers.:)

Thanks for all of your responses. On Friday, we pulled the hub carrier off the car so we could put the new bearing and hub on it. As I was reading on this site, most of the hub assemblies need to be checked with a dial indicator after assembly. Is it necessary to do this with the W202? Is there a crush washer that needs to be set to spec.? Can it just be put back together and torque the new bearing in with the axle shaft and the job is complete?

Thanks again,
Steve

looking for supplier
 

Can you give any more info about this tool kit? I have 8 seized wheel studs and could certainly use a tool like that:o