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I've never trusted tire dealers -- the last time I let them put wheels on my car was about 45 years ago. When I buy tires, I just bring my "loose" wheels with the old tires; and I change all 4 tires between winter snows and summer tires.
But I figured that my regular Volvo dealer would know better, so I didn't think anything about letting them replace my parking brake shoes on my 240 -- was I wrong!
Just goes to show you that you can't trust anyone but yourself!
Below is an excerpt (but still lengthy) from my complaint to the dealer:
"...It was time to switch from my summer tires/wheels to my winter studded snow tires/wheels, and I put the car on my jack stands and first changed the fronts, which proceeded without incident. Then I approached the rear to change those, and found that I couldn’t loosen not one but all of the lug nuts!!! We’re not talking about using the flimsy emergency tool kit in the car, but serious tools. I have a medium duty, ½” drive, electric impact driver, and I use it with an impact socket (only) to remove the lug nuts.
[I should add, at this point, that I know enough to never tighten lug nuts with this setup but in fact have the luxury of being able to take my time (unlike your mechanics) and always use a torque wrench, set to 85 Nm (this figure from my Volvo Green Shop books, sections 5 & 7, etc.)! I learned my lesson decades ago with lug nut and stud damages from tire shops that use unbridled pneumatic impact guns – so since the late 1970’s when I finally owned my own home and convenient garage, I’ve never let a tire shop put wheels onto any car I’ve owned; when I need to buy tires, I bring my wheels and old tires in my other car. And of course, I do my seasonal tire swapping myself!]
I know that your mechanics have to finish jobs fast, and that using a torque wrench is too slow and affects profits, so I cannot blame them for using pneumatic impact drivers to tighten lug nuts. But the only reason I’ve always been at ease, at least until now, with letting your mechanics do work on my car involving the lug nuts is that long ago I was (obviously falsely, at least in this one instance) assured that your mechanics always use torque sticks, rated for the particular car they’re working on (e.g., marked with a blue band for 240’s, red for 700’s, etc.), with their impact guns. There is no reason why they shouldn’t use the proper torque stick every time they put in lug nuts – with them they can still utilize the speed that pneumatic drivers offer while properly torqueing them.
Your shop, and myself, are the only people who have touched my lug nuts, and the last time (before this weekend) that I did was last March or April, when I took off my snow tires.
At first, I wondered why or how this could possible happen? Who was responsible? But then I soon remembered the aforementioned rear brake work and realized that the last person to touch those rear hubs’ lug nuts was your mechanic, in August. And of course, he had to have tightened all ten lug nuts when he finished the work!
And it wasn’t just a fluke of one stubborn lug nut. All ten of the rear (both sides’) lug nuts were frozen! And I later discovered, virtually equally over-torqued! This could only have been a deliberate act! Leaving my impact gun, I then tried to use a long handle (2 ft. long, with a ½” drive tip) with my impact socket. No joy. Left with no possible way to unfasten any of the ten lug nuts, my last chance was a longer “cheater bar extension”. Fortunately, Home Depot was still open, and I managed to find a 5-ft long iron pipe that would fit over my long handle. I came home, and with the combination of my 2-ft., ½” drive handle and this bar (employing total of about 6-ft of lever length), plus a lot of back straining for this nearly 70-yr old man, I managed to gradually loosen all ten lug nuts.
Noteworthy is that they all seemed to require the same effort to loosen! And, please consider the immense amount that these nuts had all been tightened in light of my having to use a 6-ft lever to loosen them. Ever the scientist that I am, despite being only a retired professor now, I can even offer an (admittedly crude) estimate of the over-torque: For each of the ten lug nuts, I started loosening by holding the bar horizontal and lifted the end straight up – it felt, as I was straining my back, as if I was lifting about 40 to 50 lbs. So if you multiply 50 lbs by about 6-ft, you’re getting about 300 lb-ft of torque needed to loosen every one of those ten lug nuts. And even if my lifting estimate is off by a lot (e.g., only 40 lbs), the wheels still have been overtorqued by more than twice as much, 240 lb-ft, compared to the correct 102 lb-ft (the equivalent of the specified 85 Nm).
[By the way, the wheel guide pins on both sides were also overtightened. I have to remove it each winter (and replace it in the spring) because my snow tires are mounted on older steel wheels that lack the corresponding hole to accommodate the guide pins. These are supposed to be tightened to only 8 Nm (again, per my Green shop manuals, e.g., pg 21 of Section 5’s TP-31678/1), but I needed to use a wrench extension on my regular 10 mm box end wrench to loosen them.]
So after all this, with my snow tires successfully mounted, why I am upset? Because this could have ended up with dire consequences, even tragic ones. Suppose we were out somewhere on a dark, empty road, or alternatively on a busy highway, and we got a flat tire in the rear – even worse, suppose we were out with our 2-yr old grandchild, in such a disabled vehicle – I could NEVER have been able to remove the wheel to put on a spare tire, especially with the car’s standard tool kit! Your mechanic, in so excessively over-torqueing the lug nuts, placed my family in danger! Frankly, I don’t know if even a rescue truck from AAA would have had the means (i.e., carry a 5 ft cheater pipe) to loosen those lug nuts! I can only thank god that I discovered this in the safety and convenience of my own garage, rather than on a dangerous side of the road where we would have been in danger for a prolonged period!...."
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