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.

I will check the lugs again when i get the car back for sure. I torqued the bolts myself, 100ft/lbs for sure. Checked them again after doing both sides.

Not a bad idea when performing brake or suspension work if more than just the wheel is removed to recheck the lug torque after a few days just be make sure something did not shift after driving and a few thermal cycles.

Typical. Using a complicated device to confirm a simple device. Use a bending-bar torque wrench.

I serviced nuclear reactor plants. A torque wrench had to be verified against a certified standard before use and within eight hours and in the one required direction only.

Metrology is not a simple technology for simpletons.

My vote is that the wheel wasnt fully seated onto the hub...you torqued the bolts, but once the wheel moved and properly seated the bolts no longer held it with any (or enough) clamping force. Rust on the hub, crud, etc could cause it.

The linear coefficient of thermal expansion for steel is on the order of 10^-5 K^-1 dL/L. Nope.

I guess someone is trying to run an Engineering class, the problem is we are dealing with the real world and far too many variables were left out and not assumed.

Everything from corrosion, multiple layers of materials, different materials and even tapered hub centric wheel centers. We have no idea if the wheels are OEM and the proper ones.

I choose to err on the side of caution or add an additional safety factor and verify wheel torque again after a few drive cycles. Even many national tire stores recommend a revisit to verify wheel bolt torque.

i'm wondering, is this not a thing anymore to re-torque your wheels after a few miles of driving?
i don't even *torque* mine so much, FT usually suffices. once i had a wheel off for whatever reason, i usually check about 100 miles later. it's not unusual for a wheel to re-seat itself during the first few miles after replacing, so checking tightness of the lugs is always recommended.

Ugh... such misinformation.

You can easily yield a lug bolt with excessive torque from a breaker bar/impact gun. They are almost certainly Class 10.9 fasteners, which have a yield of 940 MPa, or ~136 ksi. The hub doesn't even need to be nearly as exotic from a yield strength perspective due to the strength advantages internal threads enjoy over external threads.


OP, I'd say you either never got them properly torqued up at the last service/time the wheel was off, and never got it right on the side of the road, or more likely, the bolt threads were stretched and subsequently didn't have good engagement as the bolts were subsequently stretched more and more as they were retorqued.


The remaining lugs not being able to be removed is a bad sign as well, as that might have damaged the hub threads due to bending across the lugs since there were only 2 on there.

Alright guys i got the car back last night.
So my mechanic was able to save the hub, he had to thread 3 of the 5 bolt holes and get new lug bolts. After talking to an Indy BMW shop owner, im going to assume that i didn't seat the wheels properly.I got the bolts hand tight, put the car down all the way and then torqued the wheels so they may have gotten cocked or something. Proper way to do it is to hand tighten, put down just enough so the tire touches to prevent spinning and then torque and lower vehicle he said. Also re-check after 100 miles.

I have these brake dust shields that go inside the wheels which make it a pain to see when putting the wheel on the hub, that may have caused some issues for seating the wheel as well. The remaining 3 are coming off this weekend.
Thanks for all the help and suggestions.

I snug the lugs up pretty tight before I even rest the vehicle on the tire. Pretty easy to do with a 1/2" torque wrench or breaker bar. The mass of the wheel/tire does not rotate quickly when you really "snap" the breaker bar or torque wrench. If needed, you can even get the wheel/tire moving and the then use the rotating mass of the wheel to tighten the lugs up, braking the moving wheel with the breaker bar/torque wrench. I am guessing I can easily get 50+ ft/lbs of torque on the lugs with the wheel free from the ground.

Kind of hard to explain, but I have been doing this for years.

Had you mentioned this it is almost certainly the issue.

IMO, no it isnt.

Wheel in the air, hold the wheel, torque the bolts.

The way jfoj recommends is a good shortcut- using just a breakerbar, counter spin the wheel a quarter turn then snap the bar down in the opposite direction- with practice you will get to 50-80ftlb. THEN lower the wheel to just touching... and final torque



Personally I have a wedge of wood I slide under the wheel, put my foot against- as I turn the torque wrench, it pulls the wedge under and binds the tire.

Or, if someone is helping, have them step on the brake. Rears use the E brake.

By hand tight i mean with a socket and wrench, kind of like the snapping method. I didnt do it this way last time :/

What other issues have you had with the X? You indicated earlier in the thread that your X has been giving you issues left, right and centre! It does have the updated electronics...just curious...don't mean to hijack the thread

OT warning...

Its funny, but I can remember the first time I saw someone tighten lug wrenches like that- a back woods auto shop in eastern Pennsylvania. I was a mechanical/technical kid, and my dad was getting new tires... The guy popped the wheel on and literally in 20 seconds had gone around and tightened all 5 lugs like that.. spin/snap/spin/snap/spin/snap...

I just turned to look at my dad and the light bulb that went off must have been shining out of my eyes. He just grinned and said 'thats the way you do it'. He was a musician, not much mechanical smarts. I was 13. But he knew that I only needed to see that once.

Edit- that was before people actually 'torqued' wheel bolts!

Had few codes for a bit, it turned out to be a bad MAF sensor. Trying to diagnose it i changed the intake air temp sensor, MAP sensor. Then both DEF tanks were throwing codes for couple months and then they went away so not sure what happened there. Ground wire broke, had to put a new engine to chassis ground, batter died during the ground glitch, after that im getting the airbag and seat belt lights , which may be the positive power wire issue i just found out, then this lug issue, noticed the axle bolts are very rusted and when it needs new bearings thats gonna be an expensive job :x .
Just things here and there, i guess it could be normal for 108k mile SUV but still its no fun. Im sure i would have to get rid of the clean diesel system down the road which is $2k+ job. Thats all for now :)

THAT was your problem!

They have been on there since new, original owner had them on so idk if that was the issue. Its very thin sheet metal, but one got destroyed so im taking them all off this weekend.

Same happened to us; (X5 3.0 si) all 5 bolts went flying from the left rear wheel. We were lucky, it happened in a low traffic street after stopping on a traffic light; the wheel did not separate and car was just resting in the hub / brake disc. Had to call a tow truck and lift the car; we took one bolt from each one of the other 3 wheels, car was towed on a flat bed as we did not want to run the risk.

The hub has stripped threads, hard to say if was the root cause or a result but now we need to change the hub, and while there we will do the rear brakes as well (New Disc); we were told fixing the threads was possible but not recommended as could yield to the same issue.....