Ok, I could use some advice...

I have a 99 E320 4Matic Wagon with the original lug bolts and original wheels. New tires were put on in December. I live in MA, so lots of snow and road salt/sand...

I started trying to remove the wheels to do pads and rotors, but had a lot of trouble freeing the lug bolts. Two of them loosened with a bit of hammering, two loosened with a cheater bar, and the last one sheared off. Then I gave up and went back to the shop that installed the tires. The mechanic spent about an hour and a half trying to loosen the rest of the bolts and in the process sheared off a couple more of the bolt heads. Of the three sheared bolts, two of them came out with a bolt extractor, but the last one sheared off again down to the cone flange. The mechanic then spent 3 hours trying to drill the bolt out and ruined all of the bits on his die grinder before giving up. I have to go back later in the week after he gets some more bits.

I've never had any problems getting the lug bolts off in the past and I always hand tighten them to 80ft/lbs with my torque wrench.

So, my question is: who's fault is it that these bolts are seized on? Given their age, is there any way that the bolts could have seized so badly in the 7 months since I had the tires installed if they were properly torqued on? Or is it safe to assume that the shop completely over torqued the lugs and that's why they seized?

If the consensus is that these things happen with age and the design of the lug bolts, then I don't want to give the shop a hard time about it. However, if the consensus is that the shop must have really over torqued the bolts, then I want to push back and avoid paying 5 hours of labor to loosen/remove the bolts. The shop owner (independent shop, btw) seems to be indicating that he doesn't think they over tightened the bolts.

I've ordered a new set of 20 bolts and plan on applying some anti-seize before installing them. Is there anything else I should do?

 

I've always used 100ft/lb torque on my wheels (personal preference of mine - and I know it is not spec), but I have never had a lug nut seize on me. I have always been able to take them off without any issue.

I would think that the blame would be on the shop (especially if they were the last ones to mount the wheels) - either that or it was really, really cold when you put them on last and the metal has since expanded????

 

Assemblies of mixed metals tend to promote galvanic corrosion. Add plenty of salt and water (ice) and you have a prescription for seizure. Others have had similar problems especially with the extended shank bolts with the stainless steel cap. Also the shop probably used an impact wrench and did not adjust it for your wheels. It's a good idea to retorque your lug bolts a couple of times a year. No need to jack up the car or even tighten in a star pattern. Just loosen and retorque one at a time.

Sorry this info is too late for you but perhaps others will give it some thought.

 

I dont recommend using anti-size, that might cause the lugs to come loose.You can use anti-seize on the rim to hub surface.
I think that the shop that worked on it last over torqued them. Modern impact guns have crazy torque output in the 700+ ftlbs range.

 

threads and proper star pattern torque to 80ft lb is all that is needed.
Someone really put the power to those lugs.
Don't use anti-seize.

 

the long necked lug bolts have a well known weakiness of shearing off. I beleve they've been superceded by shorter design as a result. well documented draw back on MB forums

 

My nod is to the shop for over torquing those bolts. Never use anti seize compound on lug nuts/ bolts. Its ok to dip the ends in oil and wipe before installing. On my GT 1 Boss 302 we use that method going back to 1974. Suggest a re-torque to 80 ft lbs twice a year. Break them loose and re-tighten one bolt at a time.

 

i am hesitant to lay blame on the shop because the presumed over torquing
is based on facts not in evidence. having said that, I would try to make a case
that they were negligent, e.g. if you can determine that they do not look up the
torque for a specific make/model each time they change jobs. it's not as if
cars with X wheels uses the same as trucks with Y rims, etc etc. i'll bet they
just set it as one-size-fits-all if they're working on a car....any car.

how you can make such an compelling argument will take come creativity....as
well as their willingness to meet you half way, ie their customer service policy

 

I have used anti-seize on my lugs for 30+ years and have never had one loosen or seize. Your problem is likely due to over-torquing and some rusting in the threads. Shops generally use rattle guns, most without a torque stick. I usually re-torque my lugs when I get home from a shop where wheels were removed, like for our state inspection.

I recently bought a set of Bridgestones and the Firestone shop used an actual torque wrench on the lugs. First time I have ever seen a shop do that. I hope this sort of thing is contagious.

 

i guess the argument isn't whether the use of anti-seize is to support arguments
that the fastener will loosen or seize, rather that the application is counter to
the accurate reading and application of a calibrated torquing device. in nearly
all cases, torque is measured on fasteners dry. by applying anti-seize, one risks
over-torquing since you've now introduced a substance which wasn't expected
when the factory determine and published the torquing specifications. generally,
the added substance will lower the coefficient of friction.

 

You make a good point. A lubricant on threads will pull parts together tighter at a given torque. This gives me an opportunity to point out that I do not put anti-seize on the part of the lug bolt that contacts the wheel, just on the threads. It is my guess that most of the torque is developed between the lug and the wheel, since the radius of the contacting surfaces is much greater than that of the threads.