E70 Rear lug nuts came loose/off
 

I was driving home from an out of town trip and noticed a slight vibration on the steering wheel after leaving the mall (had it valet) so i was trying to listen/feel and diagnose it. Stopped couple times, checked the wheels lug nuts and nothing was out of the ordinary. It got little more intense and i could pinpoint it to the left rear wheel, checked the lug nuts and they were almost coming off. Doing 70+ on I90, this could have been a really bad day.
Anyways i tighten them up and after few miles it did it again. So i kept doing this all the way home, i think the bolt holes got enlarged because at some point (close to home at least) i lost 3 of the 5 bolts, barely limped home and parked it.
I cant remove the 2 bolts with a breaker bar and a socket, i don't want to break them. Its getting towed to my shop today and see what they can do. I'm thinking the rear hub needs to be replaced? (anyone have a DIY they seen?)

A week ago i did the rear brakes and torqued the wheels to 100ft/lbs, only the rear left did this. Right side is still tight. Anyone have an idea as to why this could have happened? I know i torqued both sides so that's not the issue.

Studs/nuts cleaned/lubricated? The rusty powder - rouge - is the perfect locking anti-sieze.

There was some rust on them so i scraped them with a wire brush a bit but didnt put on any lube or anti-seize

Maybe the bolts got stretched?

When this happened to our X5 (we suspect foul play), I replaced all of the lug bolts. The problem hasn't re-appeared since. It's been more than 5000 miles.

Not possible.

A particular steel alloy, that I am familiar with, yields from elastic to plastic deformation at 80 Ksi.

One does wonder about foul play since it was perfect before i handed it to mall valet but then again why would they or anyone do that? maybe someone tried to steal my wheel but left it half way ?idk

This car has been giving me problems left and right and my fiancee is giving me the stink eye lol

But it happened after you retightened, I wouldn't suspect foul play at this point.

Funny, same thing happened to my younger brother's 330 after changing tires. My dad swears he tightened them up, yet vibrations happened and all but 2 bolts (they are not lug nuts) came off on a rear left tire. Foul play was suspected, too.

Something is clearly wrong.

Lug nuts do not come loose if they are properly tightened.

BUT keep this in mind, not sure what you did during the rear brake job, were rotors replaced? Is the inside face of the rotor fully seated on the hub? Did the parking brake shoes cause a problem with the rotor seating on the hub flange?

I can only assume if the lugs were tightened, something is not fully clamped and moving around. Maybe the wheel center diameter is too small? Clamp load is the important piece of anything being properly tightened.

You might put a piece of printer paper over the hub/lug area as a test, tighten the wheel and see if the wheel flange and the face of the rotor actually come in full contact. I assume you should see embossed marks on the paper if the wheel hub is fully tight against the rotor hat face.

Also double check your torque wrench, I have seen many cases where torque wrenches are way off. Use your lug tool in the rear compartment to verify that the lugs are actually getting tight.

You could get one of these to verify the torque wrench accuracy.

ACDelco ARM602-4 1/2-Inch Torque Measurement Adapter 4-147.6 ft-lbs - Torque Wrenches - Amazon.com

Yeah did the rotors and pads with my brother, he was a mechanic for many years and has done brakes on counles personal cars so i doubt it was the brake job but definitely something to keep in mind.
Brakes were working good after the brake job, i did the bedding in process and drove for a week. The truck is at the shop now, ill see what the damage was later today. I guess its a good idea to periodically check the TQ of the studs.

Also, i dont have a spare kit in mine and i dont see any tools for the wheels?

Just use a 1/2" breaker bar or ratchet small extension and needed and the proper socket, I think 11/16" or 17" mm???

Also think back who actually torqued the lug nuts. Did one person do all wheels or was the process shared?

I NEVER allow more than one person to torque wheels and in the case more than one person is involved, I personally go around and check each wheel and all lugs 2-3 times.

You only have one chance with lug nuts and I take no chances with this process.