LAH_

Today I went down to the garage to remove my front left wheel on my A4 B9 quattro to investigate a speed dependent ticking, clacking noise. I don't know if this was the culprit but I found out that one of the five bolts was missing! And the rest were loose and one even to the point where you could unscrew it by hand.

The last time I torqued my wheel bolts was back in beginning of June when I rotated the tires and removed the anti theft bolts to replace with regular ones from Audi.

I checked and re-torqued the other wheels and most bolts were ok, some were a little loose but nothing that would alarm me. However one thing I noticed, all of the new bolts I installed back in June were perfectly torqued and all the loose ones were the old ones that came with the car.

The previous owner had replaced the anti theft bolt on the front left before me so I did not have any brand new bolts there.

I torqued everything to 128nm this time over the 120 that is mentioned in the manual. I will try and calibrate my torque wrench or maybe replace it with a reputable brand since what I have is a cheap one.
I decided to check my wheel bolt torques every six months from now on and maybe even replace them all with new bolts now. Is there a recommended period where one should discard and replace wheel bolts?

This was a very scary experience for me, thinking all the trips I made at highway speeds (and possibly higher) and gave me the goosebumps over what could have happened should the wheel come off. I would be glad to hear your advice, and anyone with similar experience.

SMac770

Make sure you're not using anything on the lug bolt threads. Should be clean and dry. Same for the lug seat surface (the curved surface that contacts the wheel lug seat).
The manual does refer to Optimol paste on the threads (and only the threads, not the lug seat surface) for anti-corrosion, but I don't live in saltville, so always clean and dry for me.

If they are the stock car wheels (and not Q5/Q7/Q8 wheels), then lug bolts should be R13 radius seat. These are Audi WHT 002 437 one-piece M14x1.5x27 R13 lug bolts? https://www.ecstuning.com/b-genuine-...ach/wht002437/

Anytime I torque the bolts for whatever reason, I follow up a week later. Never had a loose to retighten, but I do it anyway. Popped some lug nuts on my previous car coming back from a road trip, no idea what the shop did or didn't do correctly the week before, but you don't want a problem in the middle of a trip.

I'm still using the same old bolts 14 years later, no problems.

LAH_

Thanks for the input SMac770, my wheels are stock and I used WHT002437 replacement bolts. No lubricants on the thread, I saw the chemical in the manual but audi asked for an absurd amount for it so I passed. Guess they sell it bulk. I also do the torque check after the first drive and then a week or so later.

However since I had a hard time removing a wheel on my dad's A6, I did use copper grease on the flat surface, for the first time back in June. Specifically the surface where the wheel meets the rotor flat and not the conical lug seat. I can't be sure though, I might have touched there or the grease might have found it's way to the bolts or the lug seat.

Never had a problem on my previous cars either, this is a first for me.

Should I degrease the bolts and the mating surfaces just in case?

SMac770

Yeah, people use anti-seize on the wheel to rotor surface, same as the rotor to hub surface. Just not on the lug bolt contact point, the lug seat (or the rotor friction surface, etc, ie the functionally important locations). I've had anti-seize overflow into the hub threads when I do rotors; I just use paper towels and clean 'em out best I can; never been an issue.

I'd clean the bolts and the hub threads and the wheel lug seats and see where it goes from there. I've never had a problem with bolts "going bad". And that includes an idiot shop once putting F250 torque on mine one time; took an impact several seconds to break each bolt free when I went to rotate tires.

LAH_

Thanks, I will clean up and hope for the best. Glad it did not ended badly for me this time.