I just drove my car again after my sister had been dairying it for a few months. I noticed a little vibration only when driving straight or turning left (went away when I turned right). So at my first stop I checked the front right tire and Lowe and behold 3 of the lug nuts were missing. When I jacked up the corner to look a bit closer i discovered the remaining 2 were finger tight

At first I thought I'd just lost 3 of them but when I tried to scavenge a nut off the back but the threads were too far gone

The power steering was replaced a few months back and I wonder if they just forgot to torque that corner which eventually led to the failure, or is there a more common cause?

 

Improper wheel torque for sure, could have been too tight

 

Too loose more than likely.

Too tight will typically cause a sheering effect.

 

Looks like the shop forgot to tighten the lug nuts. I'd put a wrench on all wheels to verify it's indeed torqued properly.

 

Yeah I made sure all the ones were gutentight before I drove home

 

The missing ones did appear to be sheared off. My guess was as the wheel loosened maybe it started hammering on the nuts, It would be weird that two were finger tight and 3 were over tightened almost to failure

 

Do you know whether the shop used an impact gun or torque wrench? That's another possible cause.

 

That is almost always the cause, they use impact guns rather than take 2 extra minutes with a torque wrench. It would be rare for them to leave several lugs loose and others tight. Whenever I get work done at a shop involving my wheels I come straight home and loosen all lugs and torque them to spec with a torque wrench. I don't trust anyone with lugnuts, I also want to avoid warped brake rotors.

 

The last few times I needed tires I just took the wheels off the car and dropped them off at the tire place. There are too many things that they can screw up.