has anyone experienced / heard wheel studs broken while the wheel was put back on?. Had a flat tire for passenger back wheel and while the mechanic (not at the dealer) was putting the wheel back on after the fix with standard 80 Lbs torque, two of the five studs, which hold on the lugs, broke off.
Sounds like the mechanic's torque wrench might be miss-calibrated. I would redo all the nuts to make sure they are not too tight. That could cause warping of the rotor.
Toyota DOES appear to use more fragile studs on their hubs. My '04 Prius required 76 lb ft, my FJ requires 85 lb ft. My old GMC Sierra required around 140 lb ft! Trust me on this - it does NOT take much effort to snap a Toyota stud At the very least, I would use a known-calibration torque wrench to double check the torque
Are you sure that the torque is 80 ft-lbs? I just checked the torque on all my 20 lug nuts (to see if the factory over-torqued) and they were more or less at 70 ft-lbs. Either that or my torque wrench is off which is also possible of course. Edit: The owner's manual says 76 ft-lbs for 215 and 195 size tires as well as the compact spare. Makes sense, since I tried 80 ft-lbs, and it was a lot harder to get off the lugs by hand without stepping on them. The factory lug tightness I could get untightened just by putting some upper-body weight into it.
Just an FYI, Torque wrenches to get looser with age not tighter. For example, a setting of 80 Ft/lbs may only yield 75.
Over the years, most of my torque wrenches have proven to drift to being looser, as you said. Upon calibration check, at 80 they might be 75 The better pro torque wrenches tend to keep their calibration longer, and tend to be closer to calibrated values when new
Where do you guys get them calibrated - or do you just send back to the manufacturer? I am using a cheapie $20-$30 click wrench which might not be worth the postage
Many of them can't be cal'd. I had my last one checked at the Aerospace company I worked for. The lab gave me a spread sheet showing how far off it was so at least I new what it was really doing.