The wheel bolts loosened up on my 2000 S70 the other day while driving. I put rotors on the car several months ago, but torqued the wheels to 81 ft lbs. The torque wrench is working fine. Any idea as to why this happened?

Thanks,
Dave

When my car was new (V70 2000), I noticed that the bolts had a tendency to work loose even after applying correct torque, thought it was due to the chrome plating on the bolt threads.. Started to use screw locking fluid on all critical bolts by then and still do, I prefer to have all four wheels in place :)

How many steps do you take when you torque the bolts?

I tighten all to 50, then all to 60, 70, 80, then 82
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'96 855R,'64 PV544, '67 P1800, '95 855, '95 854, the first three are mine, heh, heh, 405,000 miles put on 8 bricks

Sounds like over-kill to me! I snug with impact set on low then torque to 85 ft. lb.
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Tom 69-1800S, 72-1800ES, 96-850T,2000-S70 GLT-SE

I torqued these in the star pattern. Maybe I'll raise the torque a bit. You guys are right, just so it's even it won't hurt the rotors.

Thanks,
Dave

MIJ has a good point. I once saw a wheel come off a nice car in NYC and we speculated that someone was about to get a jack when the owner came back and drove off!
I also use a drop of oil on the bolts before I put them back on. Makes taking them off much easier. They should never loosen on their own.

Klaus
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(V♂LV♂s 1995 854T, 1998 V70R)

This has happened to me several times on my 96. I torque mine to 85ft.lb. in a star pattern. In the future I will use a little WD-40 on the threads (the bolts are old and a little rusty) and torque to 90ft. lb.
TIP:
It's not the torque # that warps to rotors but UNEVEN torque between the bolts.
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Tom 69-1800S, 72-1800ES, 96-850T,2000-S70 GLT-SE

That just doesn't make sense. You want to tighten the nuts in a star pattern so that the rotor doesn't get warped, but 81 lbs should be plenty. Stop by a friendly garage and ask to check your torque wrench or compare it with one of theirs. Discount tires will do it for me.

Klaus
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(V♂LV♂s 1995 854T, 1998 V70R)

I suspect someone who doesn't like you loosened them. Bolts don't loosen on their own.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.

How exactly did you tighten these bolts? There is a method to tighten bolts properly, if not followed loose bolts can result.

Tighten one bolt till snug skip one tighten the third skip one tighten the fifth,seventh ,ninth. Continue by torqueing every other till done.

KLAUS IF YOU READ MY POST IT GIVES YOU THE ORDER FOR TIGHTENING THUS YOU SKIP EVERY OTHER BOLT SO YOU NEED TO GO AROUND TO THE NINTH POSITION NOT NINE LUG NUTS