pistolpete817

I was changing brake pads Friday in preparation for an upcoming track event. I have done this many times before with no problems. As I was finishing the torque sequence on the driver’s front wheel, the torque wrench did not feel right at 90 lbs on one nut. But not being real smart, I ignored my feeling and continue pulling. The stud broke off. This is the only wheel stud I have ever broken in 50 years of working on cars.

I knocked the broken stud out (one blow) and put the wheel back on. Now I am very wary off funny feeling lug nuts. Two others felt the same way. There was too much movement when I got past 90 lbs. I initially tightened all the nuts snugly with a 12 in ratchet wrench when the wheels were off the ground. Then I torque each wheel with a crossing pattern, at 70 and 80 lbs. At 90 lbs is where the problem came in. Most of the lug nuts had no problem at 90 and 100 lbs. But these three were wrong.

I backed off the remaining suspicious lug nuts and repeated the torque sequence with the same result at 90 lbs. Suddenly there was too much travel. I did not ever get a click at 90 lbs on these nuts.

Well the torque wrench is old, but it has always been well treated and occasionally checked for calibration. But that seemed to be a logical source of the problem. It gave me an excuse to go buy a new one at HD. Husky does make a very nice torque wrench. But that didn’t change the lug nut problem. The results were the same.

So I looked at the lug nuts. These were some Gorilla brand I bought at Discount Tire when I had a C5. They were better than the C5’s and had a good locking nut. I put them on the C6 at the first brake change. They have been off and on both cars many times. I found the OEM C6 lug nuts and replaced the problem nuts. The C6 OEM nuts torqued perfectly. I went up in 5 lb increments from 80 lbs to 100 lbs with no bad feelings or excessive movement. I got a good click at each torque level.

I then removed the OEM nuts and used the old Gorilla nuts. I had the same problem at 90 lbs.

The OEM nuts went back on with no problems.

This lug nut torque problem is beyond my experience. There are no new studs at any dealer within 100 miles of Dallas. It is at least a 3 day order item plus the time to replace it.

Has anyone else ever run into a lug nut torque problem like this? I am not talking busting it off because you got heavy handed with the impact wrench. This is hand torqued TLC.

Thanks in advance.

timd38

Sound like the studs are wore out, not the nuts. I have seen both studs and nuts wear out. I would replace them both. I use ARP studs.

pistolpete817

This a 2009 with 5K miles on it. The wheels have only been on and off twice. It is hard to accept the studs are worn out with that little usage.

saplumr

I don't think either should be worn out. I've had mine on and off probbly 20 times and never had anything happen out of the ordinary. Is it possible somewhere along the line one was way over torqued?

bob guzzy

You probably over torqued them at some point and stripped the threads they are soft and will strip easily.

pistolpete817

Over torque is the most likely cause. The old torque wrench could have been off.

Thanks all.

grr

Over torqued I'd agree with the others. Where did you read to torque them at 90#? Are you using a light swob of anti seize on the threads? If you over torque them they stretch simple as that. I just torque mine by hand with a deep well 6 point socket, long extension and 24" rachet until they all feel good and tight. X patern of course. I use a light coat of anti seize on the treads as well about every 3 races when off then back on. I have over 170 passes down the 1/4 with no issues in the C5/C6 Z06's and several hundred passes in other older corvettes and 69 & 70 Z/28 Camaro's over the years. I never fire up my air compressor to mount any tires.

torquetube

Were your aftermarket lug nuts aluminum? They definitely wear out.

Joe_G

I change my tires almost every weekend. I learned the hard way that you have to replace lug nuts every so often or they will bust your studs as you found out.

The studs seem to last a very long time but aftermarket lugs do not.

Bill Dearborn

Lubricating the studs with antisieze can cause them to be over torqued and stretched.

Bill

GeorgeZNJ

, I also stopped using my 1970's era star lug nut wrench.

Joe_G

Actually, I forgot to write, I stopped using my impact wrench to take the nuts off or put them back on. I break them loose with a breaker bar, then I use my impact only to zip them off and zip the back snug, then, I tighten them with a torque wrench.

The beating from the impact wrench made them go bad a lot sooner. They last much longer by using hand tools to tighten them.

Walt White Coupe

Please explain how a lug nut can bust your studs. Doesn't make any sense to me.

Joe_G

Trust me it happens.

Based on my experience, what happens is, when you are taking the nut off, it doesn't come free quickly like normal - it is very hard to take off for many threads...if you touch the nut at that point it's really warm...if you try to keep going, you will break the stud. And the threads on the broken stud look to be filled in with metal. Problem is when you feel the nut not coming off properly, you're screwed. I've never been able to save one at that point as far as I can remember.

Sounds crazy as I type this but the nuts definitely cause this. I stopped using cheap lugs, factory are best (but they don't look so good) so I went with a decent brand from my local parts house. They last about 6 months or so. When they start to look beat up I replace them.

Several of my racer buddies have busted studs too.

Studs are a bear to replace on the rear. Lugs are cheap.

z28lt1

When I regularly autocrossed one of my cars, I used to go through lugnuts and studs with some regularity (Probably changed a handful each year, after the first couple of years).
I'm not sure if it was the stress from autocrossing, the switching of wheels each weekend, or what, but I learned to keep extra lug nuts and studs with me at every event. The lugs would go more often than studs, but I often replaced them together because as you saw, once you try to put a bad lug on a stud, it can cause problems.

I did always torque properly (although the wrench wasn't calibrated regularly, it could have been off). I chalked it up to the extra wear we put on these cars when racing or competing.

Walt White Coupe

Just from my experience and I've been messing with cars for 50 years, I've never broken a stud. Maybe it's because I always use an anti-seize compound on the threads before I tighten the lugs. And for the worry warts out there, I've never stripped a thread from over torque either.

Joe_G

But trust me I'm not making this up, I swap tires nearly every weekend and those lug nuts will wear out after they've been on an off enough times and they will break your studs.

I think it's the cheap steel used in the aftermarket lugs.