SL/R129: Lug Bolt Head Snapped
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Lug Bolt Head Snapped
Hello y’all! I’ve seen prior forums on this but considering their age I thought it best to start a new one.
I’ve recently purchased an 1998 Sl500 with some 18inch AMG 5 spoke which look fantastic as they were just refinished. The dilemma is that they may have been overtightened by the shop. So between that and the weak design of the lugs. The ones that are designed to be more flush with the surface so they have threaded shaft, nub, unthreaded shaft, head rather than the new ones which eliminates the unthreaded shaft.
I took it to discount tire and they ended up snapping off a head. I was able to get one bolt out using a breaker bar, and the other that I tried snapped as well. I am wondering the best method to remove these. Considering the design the bolts are still torqued a lot so I don’t know if the twist in extractors will work, I’d also rather not have to drill out the bolt as it’s time consuming and I’ll likely need a new hub. What do you all suggest? I currently have the lugs soaking in penetrating oil so to ease whatever method of removal I choose tomorrow.
any suggestions are much appreciated!
I’ve recently purchased an 1998 Sl500 with some 18inch AMG 5 spoke which look fantastic as they were just refinished. The dilemma is that they may have been overtightened by the shop. So between that and the weak design of the lugs. The ones that are designed to be more flush with the surface so they have threaded shaft, nub, unthreaded shaft, head rather than the new ones which eliminates the unthreaded shaft.
I took it to discount tire and they ended up snapping off a head. I was able to get one bolt out using a breaker bar, and the other that I tried snapped as well. I am wondering the best method to remove these. Considering the design the bolts are still torqued a lot so I don’t know if the twist in extractors will work, I’d also rather not have to drill out the bolt as it’s time consuming and I’ll likely need a new hub. What do you all suggest? I currently have the lugs soaking in penetrating oil so to ease whatever method of removal I choose tomorrow.
any suggestions are much appreciated!
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I feel as though it’s not their fault… like I broke a bolt as well and I didn’t do anything wrong. The issue is more that it’s all of the bolts… I don’t even know if DT would have a solution.
Super Member
Joined: Aug 2019
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From: Lutz, FL
1997 MB SL600
They over torqued the bolts. It's their fault.
This happened to my car years ago by the dealership when they were changing out my brake fluid.
Aside from destroying your rim to get the wheel off, I would suggest what I did. Get a bi-metal hole saw of about 15 mm, actually get 2 per lug bolt. You will be cutting through the lug bolt seat so it cuts free of the shank. 15 mm is a close guess, you want to use a hole saw that's just a little bigger around than the snapped off shank. When you are about to go through the seat (take periodic measurements of your progress), go easy as you don't want to drill past the seat and into the soft aluminum of the rim.
Good luck.
This happened to my car years ago by the dealership when they were changing out my brake fluid.
Aside from destroying your rim to get the wheel off, I would suggest what I did. Get a bi-metal hole saw of about 15 mm, actually get 2 per lug bolt. You will be cutting through the lug bolt seat so it cuts free of the shank. 15 mm is a close guess, you want to use a hole saw that's just a little bigger around than the snapped off shank. When you are about to go through the seat (take periodic measurements of your progress), go easy as you don't want to drill past the seat and into the soft aluminum of the rim.
Good luck.
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Sorry for the confusion… the last shop to tighten the bolts was the one who refinished the wheels. Discount tire did not overtorque them, only break the head off as a result. Just wouldn’t want to make discount tire look bad. I’ll definitely look into that method with my neighbor who is a mechanic.
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Update… I’ve removed about half of the bolts using my impact wrench and penetrating oil. The other half have not been so successful. I have purchased a 14mm hole saw (smallest Bi-Metal Available). The issue is that it is just a bit large than the hole… probably 1-2mm. If I were to miss and cut an extra millimeter from the hole, am I going to have to get rid of the wheel? I imagine not as the bolts are tapered (I’m sure there is a better word) so It would just be a matter of twisting it another quarter turn.
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From: Norway
350 SL, R230 - 300 SL, R129 - 1964 Corvette Sting Ray Sport Coupe - Porsche 911 Twin Turbo (sold)
Easy fix.
Just take off the brake caliper, loosen and take off the screw that holds the barke rotor/disc in place and i am sure you will see the bolt sticking out a part of the brake rotor/disc so just screw it out
If you absolute do not want to take off the brake caliper and rotot use a hard metal rod and place that on the broken off bolt and tap it a liitle (not to hard) with a hammer and use the broken screw extractor in the hole you drilled and the bolt will come out..
Just take off the brake caliper, loosen and take off the screw that holds the barke rotor/disc in place and i am sure you will see the bolt sticking out a part of the brake rotor/disc so just screw it out
If you absolute do not want to take off the brake caliper and rotot use a hard metal rod and place that on the broken off bolt and tap it a liitle (not to hard) with a hammer and use the broken screw extractor in the hole you drilled and the bolt will come out..
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Super Member
Joined: Aug 2019
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From: Lutz, FL
1997 MB SL600
No it isn't.
There is precious little room between the caliper and the rim. Even if you removed both caliper bolts, the caliper will not lift clear of the rotor with the rim on. And how on Earth are you going to access the rotor hub face to remove the retaining bolt with the rim on?
The reason the bolt broke off in the first place was because it was over torqued, if it won't come off with a 3 foot breaker bar; it sure isn't coming off by tapping with a rod or a screw extractor.
There is precious little room between the caliper and the rim. Even if you removed both caliper bolts, the caliper will not lift clear of the rotor with the rim on. And how on Earth are you going to access the rotor hub face to remove the retaining bolt with the rim on?
The reason the bolt broke off in the first place was because it was over torqued, if it won't come off with a 3 foot breaker bar; it sure isn't coming off by tapping with a rod or a screw extractor.
