I have a 97 Volvo 850 (non-turbo). Living in Canada, one has to change from summer tires to winter ones. Last year, I did the change-over myself, from winters to summers. A few months later, while my friends were driving the car, the front wheel flew off on the highway. Fortunately, after an expensive tow back home, I was able to piece the car back together. I replaced the worn-down brake rotor and banged out the fender. The car drives fine now.

I also bought a torque wrenchand replaced the wheel bolts of that wheel to ensure that the wheels would be properly fastened in the future.

A few weeks ago, I was driving back home with my family and I heard a very loud sound. I pulled over and realized that the bolts on the back two tires were finger loose. What is the cause of this and are there any solutions? I use a torque wrench set to 81lb ft of torquethe specs I found for the 850. Should I use lock-tight? Should I replace all the bolts on all wheels? Is there another solution that anyone knows about?

I am also curious about the reason. Could it be drastic temperature changes that loosen the bolts? Am I using the wrong torque specs?

Thanks for your help.

Nate

 

Ok,

#1. It would have to be a pretty DRASTIC temp change to cause them to loosen like you mention.

#2. I have NEVER used a torque wrench on a lug in my life and have NEVER had a wheel loosen unless there was some other issue. Tight is Tight.

Couple of questions.

1. Are they the stock wheels, hubs and lugs?
Aftermarket wheels or lug bolts could have the wrong taper and not seat properly.
Also aftermarket wheels might not have the correct hub size and be preventing the wheel from properly seating.

2. Are you sure that it was 81 foot pounds not 81 inch pounds?
81 foot pounds is pretty stout.

 

Thanks for the reply:

#1. It would have to be a pretty DRASTIC temp change to cause them to loosen like you mention.

The temp did go from about -15 to +8 C in the space of a day. But none of the other cars in the driveway had a problem.

#2. I have NEVER used a torque wrench on a lug in my life and have NEVER had a wheel loosen unless there was some other issue. Tight is Tight.

Couple of questions.

1. Are they the stock wheels, hubs and lugs?
Aftermarket wheels or lug bolts could have the wrong taper and not seat properly.
Also aftermarket wheels might not have the correct hub size and be preventing the wheel from properly seating.

Yes they are stock wheels and lug bolts. Actually, the summer wheels are from a V70, the lug bolts, as far as I know, are stock, and I don't think the hubs have been changed. The winter rims are the stock steelies.

2. Are you sure that it was 81 foot pounds not 81 inch pounds?
81 foot pounds is pretty stout.
81ft lbs (110Nm) is what I dialed in to my wrench. They were pretty tight.

Could it be bad alignment? Or perhaps just bad luck?

Thanks,

Nate

 

It could be a bad torque wrench. I had the same thing happen, and it happened several times over the course of three days. When I checked the torque on the wheels that weren't a problem they read about 120 lb/ft on the wrench even though they had originally been torqued to 81 lb/ft. I took my torque wrench back to Advance Auto where I bought it and exchanged it for a new one.

...Lee

 

Different Volvo wheels use different lug bolts. I know this for a fact cause when I hit a curb in Colorado in my 95 850 Turbo I messed up two of the Columba wheels, so I bought some 15" wheels for it and I had to get different lug bolts for the new wheels. So you have to make sure you have the correct lugs for the wheels you are using. When you switch from summer to winter or vice versa you may need different lugs too.

 

I agree with Jim, an incorrect taper will certainly cause the problem and I am 99% sure the issue is with the steel wheels. They tend to have a rounded type socket and the lugs tend to be tapered for the alloy stock wheels. Also since the problem is with the steel wheels the temp issue should be a non issue. Steel contracts so much less than alloy that you would need to have put the bolts on at like 150 degrees C and it would have to get down to like negative 150 degrees before there would be an appreciable difference in thickness.

I suggest a couple things

1. Remove the lugs and check how they seat in the wheels. There should be a lot of contact area. Also, check with a dealer for part #'s on lugs for V70 stock alloys and 850 steel wheel lugs. They could also show you each and it will probably be apparent if the shape is different.

2. Once you have confirmed that the correct lugs are being used then I would clean out the thread area with a small wire brush. Clean the lug threads, put a little never seize on the threads and the sockets of the wheels and tighten. With steel wheels you really can't over tighten them (unless you weigh like 400 lbs and step on the breaker bar!) Again, I never use a torque wrench I just tighten as far as I can by hand then give a good shove with my body weight. (100KG or 230lbs.) So with a 2 foot long breaker bar that works out to about 120 to 140 lbs.

 

From volvospeed: "improperly torqued lug nuts are the number one cause of warped rotors"

A torque wrench is fairly cheap, set it and forget it!

 

I have never used a torque wrench on my lug nuts and I have a warped rotor once on a Volvo. Used to warp like crazy on my Suburban though. I think if you have tightened enough lug nuts you just kind of know how tight to make them. I never make mine as tight as I could, but I make them pretty tight or Gooden Tight.

 

Hi Nate,

To answer your question: NO; if the wheels were properly installed and tightened, then that temperature swing would not cause them to loosen.

One of two things is happening:
[ol][*]Either you are not qualified to install wheels on a vehicle (am not inferring that is the case; just stating the obvious) or,[*]Someone is f-g with you and loosening your lug bolts when you're not looking. Maybe they think they are being funny, but this is no laughing matter.[/ol]That wheel coming off on the highway could have injured/killed your friends or someone else on the highway; a wheel rolling down the road at 100 km per hour is like a small runaway vehicle.

You mentioned the rear wheels came loose; did you install/torque them the same as the front wheels? Did you ck the fronts after this incident? If I were you I would park my car in the garage or install a video cam on my driveway. Something is up and I would get to the bottom of it...

Let us know what you find...

 

>Someone is f-g with you and loosening your lug bolts when you're not looking. Maybe they >think they are being funny, but this is no laughing matter.

So far this seems to be the likely possibility. Try marking the bolts with a thin oil-based pen such as a Sharpie to see if the alignment mark has shifted.

I would use a good quality torque wrench on aluminium wheels. A good torque wrench usually costs at least $100 (anything less expensive is either made in T@iw@n, Chin@, etc...) and must be calibrated at least twice/year (once/year for aircraft use). Over-torquing aluminium wheels can crack the wheels.

Unless your alignment is so messed up that you feel vibration, and you have been using the original wheels & lug bolts, I cannot imagine what else could cause the wheel to fall off. However, before the wheel falls off, you should have felt undeniable vibration.

No, a drastic temp shift should not loosen lug bolts. If it does, all airplanes flying in the world would be falling apart in the air (the ambient temp at 35,000ft can be as cold as minus 50 degrees Celsius versus -30 to +40 degrees on the ground).

The factory manual specifies 80ft-lbs. My Snap-on torque wrench is calibrated in in-lbs so I set it at 960in-lbs (80 x 12), FYI.

Wait for Tech to see what he has to say.


JPN

 

I would certainly hope that noone is "effing" with you! This could be considered "attempted murder" or manslaughter. I am still leaning towards the lug nut style issue.

Info from FCP Groton

Alloy wheel lug part #
3546899
This aftermarket wheel lug bolt for your Volvo is made by Dorman products. This is only for models that have alloy wheels. If your vehicle is not equipped with alloy wheels, you need part number 3546651.
See the different part #'s? Usually means different parts.