Volvo Dealer Service (Bad)

Not trying to defend your dealer, but pretty much all dealers and quick tire shops use air guns to tighten lugbolts. It's just quicker that way. They don't care.

Whenever I have work done on my car that involves removing the wheel(s), I always retorque them with my torque wrench when I get back home.

Even worse from too much torque is uneven torque, ie. 100 lb-ft to one lug, and 200 to another on the same wheel. That is what may lead to warped rotors.

Cheers,

Pete

The loosening torque of a nut can often bear no relationship to the tightening torque, especially if is a while since it was done up. In scientific terms, the frictional forces acting upon a static object (the nut you are trying to loosen) are greater than than those acting upon the same object when it is moving (the nut you are tightening - you will only get an accurate torque setting if the nut is moving when the torque limit is reached). There are also the additional complications of crud and corrosion having working their way in since you tightened it, or of any lubrication or moisture having dried out. So a 200 ft-lb loosening torque does not imply a 200 ft-lb tightening torque. I often find I need an extension bar to loosen wheel nuts.

Yep. For those without a torque wrench, the correct torque is between

2 and 3 grunts.

I went to Kwick Phit a few weeks back to have both front tyres changed and the tracking done. They amazed me by using a torque wrench dialled to the correct lb/ft to put the wheels back on. They used the air gun to take them off, but so would I if I had one. Most impressed. Even more so when they didn't try to sell me anything else. Mebbe the

sign in the back window did the trick..... ; ) And the tracking job was so good I could go back into the load area of my 745 to change the cd changer cassette if I wanted and get back to the wheel while travelling down the motorway, not that I would....

Stuart

Stuart

I understand what you are saying, and agree that it is generally true, but disagree that it applies to this case for a couple reasons- this was too much torque to attribute to crud, and the opposite wheel on the same axle came off normally.

I've taken my wheels off and put them back on again enough times on all my cars, whether they've been on through winters with salty roads, or more benign summers (like this case) that I think the one wheel was overtorqued. The steel wheel spec is 80 ft-lbs. Going from that to standing on a 15" johnson bar doesn't add up. I normally retorque my wheels after getting new tires. I've had to work hard to loosen them after a tire monkey used an air wrench one time, and not had to work hard a different time when a tire tech used a torque wrench. Usually I find I do need a little more torque to get them loose (say, just over 100). The wheel that I put on (doing something unrelated), long before bringing the car in to the dealer for work, came off normally.

Anyway, thanks for pointing out a couple valid things, but in my particular case, I respectfully submit that the dealer still overtorqued my wheel.

There is an accessory available for air (or hand) ratchets specifically to avoid overtightening wheel nuts...

Essentially, the gadget looks like a 1/2" drive extension, but is usually colour coded and come in a set of about 5. Each one has a limiting torque at which they begin to freewheel. The air ratchet is simply used until the torque limiter cuts in, then go to the next nut, etc... Different models of vehicle specify different tightening torques (usually based upon the thread size), and hence each colour coded piece is intended for certain models of vehicle. It is some time since I played with them, but ISTR them having a pop-out button that popped at the preset limit and had to be reset for the next nut.

I am a qualified mechanic, and I always use hand tools to do up wheel nuts. If I had a set of torque limiting extensions as described above, then and only then would I use an air ratchet to put wheels on. I don't work as a mechanic anymore, and couldn't justify the cost ATM, so I'll stick with a wheelbrace or ratchet and socket. Still need a breaker bar to remove them sometimes, though.

Even shops that have air guns have methods to get the correct torque if you make them use them.

After getting tires at Sears, I had a flat. I couldn't get the lug nuts loose. I called AAA and they couldn't either. They towed it into a garage and used a 6' extension on a wrench to get it off. When I took the tire in to Sears to get it fixed, I made them torque all of my lug nuts. They didn't like doing it, but they did have the tool. It was a socket extension for the air wrench that looks sort of like and hour glass in that it is thinner in the center. It must twist when it gets tight.

Now, whenever I get tires or get them rotated, I ask to have the lug nuts torqued.

The air guns don't provide a constant rotating force, they hammer then relax, hammer then relax. The tool you're talking about acts like a spring. Imagine hammering in a nail with a spring on top of it - assuming you don't bottom out the spring, the amount of force you can transmit to the nail depends on how stiff the spring is, not how hard you swing the hammer.

LOL reminds me of that episode of the Simpsons... "Cruise control my good man!"

Jim -

Do not know where you live so... If you are north of JAX let me know, and I'll give you the name of a good-guy mechanic who thinks Volvos are the bees' knees. His shop is so good that I buy cars according to what he and his mechanics enjoy working on. He's gotten me 227,000 miles on a '91 745 that has been "rid hard and put up wet." And he tells me I have 170,000 miles to go.

TC snipped-for-privacy@earthREMOVESPAMlink.com (If'n you take out REMOVESPAM you might find my address)

Jim Carriere wrote:

When my daughter went to UNF, Al of Al's Volvo was a life saver.

Had 79 245 D, 81 240 D, 86 240 320,000mi and running fine when traded 94 944 Green 257,503 mi CRUNCH Parted out Have 94 944 White 149,000 The New one 94 944 Maroon 135,000 mi

Well, thanks (and to Tintagel Cogges), but I'm moving in a few months, so local long term care here isn't really going to be an issue to me.

Most shops use torque bars on their guns, exactly what one of the people mentioned.

You can buy them in several different torques, ie: 80 lb/ft, etc..... No matter how much torque the gun is putting in a forward direction, it will only apply 80lb/ft torque. (lb/ft = ft/lb interchangable)

They are actually quite reliable, but even my shop (Sam's Garage) uses this torque bar on STEEL WHEELS only!! Every time they do an aluminum wheel, out comes the torque wrench AND anti seize compound!!!

Your nut may have been stuck because it was galled against the tapered surface of the wheel, basically creating a lock washer.

Most impact guns have wayyyyy more reversing torque than forward, my gun has a max of

160ft/lbs torque and 400ft/lbs reverse at a specified air volume, I use a high quality CP tool, most shops use similar (blue point).

I wouldn't blame the dealer, blame the mechanic.

My Toyota dealer did this to me, I took it back, and they gave me a free oil change.