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Good evening gentlemen, I find myself in quite a predicament once again.
A couple of months ago while fueling up, I glanced down at my passenger side rear rim and noticed that 4 out of my 5 bolts had snapped off of the rotor. Luckily I noticed before it was too late, and I was able to have the C towed to my local indy. Their conclusion was that whoever previously installed it had either over torqued the bolts at install or it was a faulty part to begin with. They managed to drill out the remnants of the 4 bolts that broke off and replaced all with new parts.
All was good until once again, while parking my car in the garage tonight, I noticed that 1 of my bolts from my driver side rear was missing. Since the repair, I've driven about 5k miles so it should fall under the shops warranty timeline.
Has this ever happened to anyone else? I'm concerned that this will be an ongoing issue and it's an uneasy feeling knowing that my wheel bolts seem to keep failing on me.
Just for reference I am sitting on 19's and lowered on H&R springs. Also extended bolts were installed in the rear on both occasions. Could this be a catalyst for the failures, or could it be the shear torque from heavy accelerations?
Get one of the failed bolts and post a photo. Check to see if there is a band worn onto the seat of the lug bolt instead of an even unmarred surface. What brand of wheels are the 19's?
1. oem wheels use ball seat bolts, but most aftermarket wheels use cone seat bolts. tell us what type of wheels you have on the car and we can try and figure out if you're using the right bolts.
2. when the shop fixed the passenger side after the first time, did they check all the rest of the wheels as well? or did they just leave them as is?
3. do you have spacers installed? i thought you only needed extended bolts if you had spacers.
edit: forgestars definitely use conical seat bolts...well at least the cf10's i had for a little bit did. if you're using the oem bolts with those, those are not compatible.
Last edited by JPetros2008; 02-22-2015 at 11:38 AM.
Get one of the failed bolts and post a photo. Check to see if there is a band worn onto the seat of the lug bolt instead of an even unmarred surface. What brand of wheels are the 19's?
I'll post some pics later today. Wheels are Forgestar F14's, not too sure if they are hubcentric. I let them handle everything as far as getting the right fitment.
Originally Posted by jcfay
do you know if they followed the torque specs? That's frigging super dangerous...
First installation was done by a vendor on here, so I'd hope so. The second time around my indy tech confirmed with me that they installed the bolts according to spec.
Originally Posted by mr747
Get some extended wheel lugs from acg well worth the extra cash
Thanks, at this point it might be a necessity.
Originally Posted by Merc63
Get better bolts and make sure they are the right seat type. Install them yourself with torque wrench. Also verify they are theaded in enough.
^ That's the plan as soon as all this is sorted out thru my indy.
The wheel is centred on the hub. Cheap wheels have a generic bore size to fit a myriad of cars, so if you don't want them to wobble, you put a plastic or aluminium (better) ring in the tapers the bore to actual hub diameter.
The wheel is centred on the hub. Cheap wheels have a generic bore size to fit a myriad of cars, so if you don't want them to wobble, you put a plastic or aluminium (better) ring in the tapers the bore to actual hub diameter.
ive never seen a factory wheel bolt fail. Even when over torqued they dont break in the rotor, the heads just pop off. Ive only seen this on one occasion on a 20yr old benz with rusty lug bolts i couldn't remove. i tried my 3/4" impact on them - 1200 lbft of torque for about 30 seconds is how much abuse they take before the heads pop off
Any chance the installer used a lube like anti-seize or ?
I've not seen a MB lug failure but I have taken part in failure investigations of critical fasteners. Many involved metallurgical analysis of the failed component and in most every case, the failed fastener was over torqued. There have been a few where the incorrect grade material was used.
The ones that come to mind is when anti-seize is used. I've seen quite a few threaded studs and bolts yielded because the installer did not recognize that there is a torque reduction if anything other than light machine oil is used.
Once a bolt, stud, etc. is yielded it is trashed.
The reduction varies with the product. To add, these products are for use on threads. If too much is applied some will likely get on the face and get smeared on the mating surface of the lug and the surface it connects to. This requires an additional torque reduction.
1) First of all don't ever trust anyone with critical items on your car. I know there are a lot of good shops out there but you never know if the guy working on your car knows what he is doing or really cares. So if you ever get your tires installed somewhere always recheck the torque of the bolts yourself to to ensure it is done right.
2) As far as I know, Forgestar wheels ARE NOT hub-centric. That means that you DO NEED Hub-Centric Rings.
What that means is, hub-centric wheels fit snugly on the wheel hub and the bolts just hold the wheel on place. Therefore most of the weight and stresses are transferred directly to the wheel hub. If you use a wheel that is not hub-centric then there is a lot of stress applied to the lug bolts and the wheel may not sit perfectly centered over the hub. This could possibly cause lug bolt failure or wheel vibrations.
3) Also, you can remove one lug bolt and check to see what type of bolt seat it needs by using this picture as a reference:
4) I am not sure what length bolt the Forgestar F14s use but you can measure that yourself. You can watch this video:
I appreciate the thorough response. I'll definitely keep all of that in mind. Going in early tomorrow to get all this handled, and possibly even putting the stock wheels back on.
Bought wheels from Modbargains. Tires from Discount Tire. I go through a set of rear tires every 9 months or so.
Wheels were bought about 1.5 years ago.
Problem:
I found the top 1/2 of a lug bolt in my driveway 2 weeks ago. I was VERY concerned as I have a long commute to work. Took it to Discount Tire. They said I would be ok for a couple days. Needed to buy a new lug bolt. I went to local places (discount tire, NTB, O'Riley's) and couldn't find any black conical lug bolts.
Bought a new lug bolt on Amazon. It took a couple days to get here. While waiting for the new lug bolt, I ordered new rears (Conti's) from Discount Tire.
The new tires arrived today. Discount Tire guy pre-inspected the car and let me know that a lug bolt was missing from right rear (my issue was was with left rear???). After some poking around, I realized that I was missing lug bolts from both rear tires and 2 more were sheared and about to fall out from my right rear. Of the 10 lug bolts on my rear wheels - 4 were sheared off.
I am at a loss for words. I should have lost a wheel (or two) today. I got very lucky that I made it on 2 lugs today.
The advice from discount tire today was to get a tow truck and take it to mercedes. I think that Modbargains is sending me a new set of lugs. The advice i got from a "car guy" friend was that the lug bolts are aftermarket crap that was over torqued.
Discount Tire was unable to help me. I took my car to NTB and they backed out the broken lug bolts. They took bolts from the front tires and now I have all 4 wheels on each with 4 out of 5 lugs on. I'm going to the MB dealership tomorrow to buy OEM lug bolts.
I'll post more info in a couple weeks after I get everything fixed and have an idea if I'm still shearing lug bolts.
BE CAREFUL!!!!!
Check all of your lug bolts tomorrow morning! For some reason my rear wheels are shearing lug bolts. This is happening on other models (see WRX and M3 forums). This could have been a blog about a lawsuit if I had driven a couple more miles. Or had the lug bolts all broken while my wife was driving my car with my kids - this blog would be about 3 unnecessary fatalities.
Sounds like the hubcentric ring adapters weren't installed (assuming those wheel used them). The Forgestar adapters are metal and a very tight fit. They need to be installed by being tapped into place carefully. It takes a little time to do it right. The good thing is that once in they are permanent, they're not going to melt, degrade or fall out.
02-22-2015, 01:30 AM
