Hi Guys,

So - I was putting a wheel back on, and couldn't get up to 100 ft/lbs on 3 of my lugs. I kept turning on one of them until it snapped since I couldn't get adequate torque.

I plan to get to mid-ohio on the 17th so don't really have time for too much dealer shenanigans - has anyone had this happen to their car? Also are there upgraded studs available? I might just want to go that route - not sure how big of a PITA it is.

Thanks!

 

The C7 is pretty close to the C5 and C6 in this area so the same thing you would do with them would apply with the C7. I would think again about using the dealer since the car is under warranty and they might pick up the job under warranty. It is just a couple of hour job and they should be able to fix the problem while you are waiting.

Did you find out why the wheel didn't torque down properly? Things to look for are burrs on the hub that interfere with the wheel seating against the rotor properly, bent wheel, something uneven on the rotor face. Do you have aftermarket two piece rotors?

Front or rear wheel? Fronts are pretty easy to replace the studs while the hubs are on the car or a little more difficult if you want to remove the hub. Rears get a little more difficult due to the parking brake backing plate or the axle going through the hub.

The simple way to do the fronts is to remove the rotor and caliper. Once that is done turn the hub so the broken stud is located where the little notch at the rear of the spindle is located (right behind where the caliper was). Then take a 3 lb short sledge and hit the broken end of the stud one good solid whack, that will knock the stud out of the hub flange. You can replace stock length studs very easily by placing them into the hole in the hub flange and then using an open ended lug nut with a washer between it and the flange to pull the stud through the hole and seat it. You want a good 1/2 in impact gun to do this (either electric or pneumatic). If you want more threads than stock you can go with an auto parts store aftermarket replacement such as a Dorman stud which will give you around a quarter inch more studs while keeping the same length stud. Otherwise you are into using longer studs from companies like ARP which can be tougher to angle into the hole in the hub flange due to their length. If that happens you need to pull the hub which means disconnecting the ABS connector and removing the 3 hub bolts that hold the hub to the knuckle. They are Torx head bolts and if somebody didn't Locktite them in they are not to bad to get out. The bottom bolt requires dropping the ball joint stud a little so you can get to the head.

To drop the ball joint stud remove the nut at the top and take your trusty 3 lb sledge and use it to hammer the bottom of the knuckle where the ball joint stud is inserted after a few good whacks it should come loose. It can be difficult to see if the stud moves so after each whack try and move the LCA up and down. If it moves the stud is loose. Then you can get to the lower bolt. Before trying to remove it look behind the hub flange and you will see the other end sticking through the hub. Make sure to soak it with some penetrating oil to get the dirt and crap off before trying to remove the bolt. Then you can put the hub on a large vise and use the hammer to push out the studs and the washer and lug nut to pull the new ones in.

The rear is done pretty much the same way. The knuckles in the rear are identical to the ones in the front just on opposite sides of the car. If you want to try and replace the studs with the hub on the car you need to locate one of the holes in the hub with the notch and determine exactly where you drill a hole in the backing plate that will permit you to pass a stud through it and into the hub flange. There is a clip in the backing plate that is used to locate the parking brake mounting spring so make sure you are far away from the clip to keep from compromising it's strength. Otherwise you need to remove the rear hub which at least requires dropping the LCA, removing the rear tie rod end and then freeing the hub from the axle. The Service Manual shows pulling the complete knuckle out by removing the top and bottom ball joint studs.

I haven't had the enjoyment of doing a rear replacement but I have seen some people having to use a slide hammer to free the hub from the axle.

Bill

 

Hi Bill,

Wow, thanks for a tremendous reply. I really appreciate it.

It's a front. I had loosened the studs because I was planning a brake pad change, but decided against it for timing. I just cracked them loose, then went to tightening.

Thanks for the summary on what needs to be done. I'll call the dealer Monday morning. I don't think I need longer studs, I was just checking to see if there was anything strong/more durable that might be more suited for track usage.

I've never had the front wheels off, so I was very surprised for this to happen - especially to 3 different studs.

How much torque do you think the studs should be able to handle?

Thanks!

 

sounds like you need a new torque wrench. My buddy did the same thing to his Rousch mustang, except it took him snapping off 3 studs before he figured it out duh. I still give him a bad time about it.
Snap on has a nice digital one, albeit pricey, about $350., but you will never snap off another wheel stud.

 

Yeah I need to do that. The weird thing is that the other 17 didn't have any trouble. Maybe I am right on the edge - but the other side of the car (the side I did not loosen) took maybe 1/32nd turn before clicking.

Thanks for the reply and idea!

 

I'm convinced there is something wonky about the studs on the C7. A year ago I had my C7 Z51 at VIR and went to swap front wheels. I couldn't get the studs to tighten either. I tried three different torque wrenches and they just kept spinning. I ended up getting some open ended nuts from one of the race team guys and just calling it a day.

Yesterday I was putting the wheels back on my C7Z and I could tell they were turning too much so I stopped, backed them off, and then retorqued them. There is some kind of blue substance on the studs and I wonder if that is causing the issue.

BTW, been changing wheels all my life and changed wheels on my C6 probably hundreds of times without issue. It's just been with the two C7's I've had.

 

I have the exact same problem at the Barber track as we speak. C7Z06 2015.

3 or 4 of the nuts will not tighten properly, I stopped turning before they stripped or snapped.

Tried 2 different TQ wrenches.

One of the nuts kept turning at 80 ft. lbs.

Being I'm at the track away from home I'm going to leave it alone for now. When I get home I will get to the bottom of it.

Very strange.

 

Yelp its very common. I stated this problem back in Jan on my first track event. I found that after they got very hot and cooled a few times the spinning went away.

 

So are you guys going to change them out for ARP's or something?

 

I've broken lots of studs on my C4, none on my C5, and I don't remember breaking any on the C6. I'm sure that GM uses an outside supplier for them, so maybe it's a quality control problem from a vendor. If it happens again, a switch to ARP might be a good idea and maybe keep a few spares around.

 

I run longer ARP studs and open lugs on my C6Z but at this point I don't have any plans to change on the C7Z.

 

Yes. During wheel swap broke rear driver side stud at less than 100ft lbs. Aggravated dealing with dealership. Stud was broken at shop they recommend to do tire swap as they had no time before I took off cross country. They did fix stud and charged me 6.5hrs!!! I have a snapshot of the GM flat rate guide which shows 2.8hrs. Hendrick Chevrolet in Birmingham.

 

Sounds like typical hendrick dealers.

 

I think mine broke because my lug ran out of space. Otherwise I think they just stretch - freaks me out. I don't want to crash because of an over-stretched lug.

 

I ordered ARP studs and titanium lugs from Katech - but I started looking for a wheel stud removal tool and I've found dramatic differences in price. I'm sure there are quality differences, but can someone weigh in here? Seems like there is an OTC version that's in the $230's - seems expensive for a C clamp.

Here's one on eBay for about $100 shipped, but frankly still seems expensive.

http://www.ebay.com/itm/New-Ball-Joi...-/181689124366

Am I missing something here?

 

This tool works on the front hubs for removing wheel studs:
http://www.harborfreight.com/3-4-qua...tor-99849.html
The rear is a pain because of the parking brake. Need to remove the hub from the upright to get the studs out.
For install get a couple of 12x1.5 mm open lug nuts and some washers.
Use the lug nut with washer under it install the new studs.
Good luck

 

Anyone else have any word on broken wheel studs (Z07 package…)?

 

That labor is probably correct for the recommended way to change the studs. A mechanic can probably do it the short way but will need to be directed to do so by you. That is how the dealer mechanic handled a broken stud on my C5. He came to me and said if I follow the manual I will have to do all of these things, if you give me permission I can do this, this and this, drill a hole here and get the job done in less than an hour. C7 is suspension is pretty close to the C5 layout so it is likely the same thing can be done on it as well.

Bill

 

You can spend a bunch of bucks for a special tool or spend a few dollars for a very well designed and built 3 lb short handle sledge that will drive the studs out with just one solid whack. A lot easier, cheaper and the tool does a hell of a lot of other jobs as well. A great addition to the tool box while the special tool is going to be sitting around taking up space most of the time.

I had a mismatch between my aftermarket rotor hat and aftermarket wheel mounting face which prevented the lugs from tightening properly resulting in all 5 holding one wheel on breaking off. To get the wheel remounted so I could put the car on the trailer I took the sledge and hit each stud once to get them out. It didn't take me as long as it would take to install that tool on just one stud.

Bill

 

Let me start by saying I have a REALLY good dealer. The shop foreman always helps me out. I called him in the morning without any appointment or anything - he will drop everything and fix my car. He'll do it himself if he doesn't have a qualified tech available. That said, he couldn't fit the ARP stud in without pulling the hub, so under warranty he pulled the hub and put 5 new ARP studs in for me. I supplied the studs. As far as labor goes, he had the entire job done the right way (pulling the hub) in about 1.5 hours (front). The rear might take longer.