How to remove broken caliper bracket bolt?

On Euro cars that use lug bolts they definitely have a purpose, without them the rotor can get out of alignment with the lug holes. On Japanese stuff that use lug studs it is for assembly line ease only. There is a negative to them though it prevents rotating the rotors on the studs to correct run out, if it has studs I toss them.
Thank you for the reassurance. 🙏

And what do you mean when you say “rotating the rotors on the studs to correct run out?”

Is this something I should be doing?
 
It is always a good idea to do this, the hub face must always be perfectly clean with no rust or buildup. New rotors are usually within spec but if there is a minor deviation from spec sometimes rotating the rotor 90 or 180 degrees may correct it, if it is substantially out of spec and everything is clean then a plate my be used, you can get these at parts shops like Napa. There is a lot more to doing brakes properly than just throwing a rotor and pads on.
Watch a few videos, you can get the tool from HF, not the best but good enough.

 
It is always a good idea to do this, the hub face must always be perfectly clean with no rust or buildup. New rotors are usually within spec but if there is a minor deviation from spec sometimes rotating the rotor 90 or 180 degrees may correct it, if it is substantially out of spec and everything is clean then a plate my be used, you can get these at parts shops like Napa. There is a lot more to doing brakes properly than just throwing a rotor and pads on.
Watch a few videos, you can get the tool from HF, not the best but good enough.


Excellent information - thank you, Trav!
 
I read it’s just for ease of assembly at the factory so when they put the sub frame into the car or whatever everything is tight and the rotors won’t fall off etc.?
That's really all they're for. I'd say most cars do NOT use them and people get along fine. You can always use a lug nut to hold the rotor in place when you're doing brakes but the pilot fit on most rotors and hubs is sufficient that the rotor can stay where it needs to stay. On an assembly line, I'm sure there's some less-than-smooth movement that could make the rotor fall off.
 
I’m thinking it needs four NEW bolts. Two for each caliper.

If he grossly over torqued this one using a pipe, what are the odds that the other three haven’t been stretched?

Have you tried strectching a 12.9 or even 10.9? They are likely overtorqued but generally snap before stretching in any clearly visible way.

4 new bolts indeed.
 
A good point, I said stretched, meaning pushed to the point of elasticity, and meaning, “damaged”. I should’ve just said damaged.

Bolts are cheap.

I am still a bit baffled by tightening with a pipe, no measurement, and snapping off bolts, instead of using a torque wrench. High strength bolts, and safety critical fasteners, are the instances where torque wrenches are really needed.

Not a pipe extension and OMG tight, hoping for the best, and on occasion, encountering the worst.
 
Just a note re the attached photo... and with specific reference to the two threaded holes evident (180° opposed) for rotor removal: they're often pretty small by way of diameter... and so if I use them or try to use them for rotor extraction off the hub, well, I don't attempt very much with the rotor extraction screws for fear of stripping them. Rather (and this would not work with the OP's prb of the caliper frame/steering knuckle bolting snap-off...) I remove caliper bracket from knuckle, and I use the bolt + 2 nuts (in ea. hole) method (and sheet metal against the rotor where the bolt/nut bears against) to very satisfyingly extract the rotor from the hub. Also, of course, penetrating fluid. I also use a mite 'o NeverSeize upon reinstallation to try to avert the prb next time 'round.
 

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Usually a good tap with a hammer brakes the rust seal and the come off. But if the hub is close in size to the bell inner diameter you can be in for a treat.
 
Usually a good tap with a hammer brakes the rust seal and the come off.
Usually.... When we replaced the brakes on my wife's Fusion the first time after we owned it (this was a Wisconsin, then Ohio car, FWIW), we had to whale on it A LOT with a rubber mallet, to the point my wife came to the garage and asked why we were beating on her car. When I replace rotors, I used to put anti-seize on the hub face and outer diameter ring but have since switched to (name escapes me) a semi-gooey, odd-smelling spray (Eric from S Main Auto uses it).
 
It was primarily because of the noise. 4-5 blows with a metal hammer and we stopped and switched !
 
It was primarily because of the noise. 4-5 blows with a metal hammer and we stopped and switched !
I keep earplugs in the garage for just this…a good whack on any solid metal part is incredibly loud.
 
My method of using the steering knuckle (usually) unthreaded holes prevents any possible damage to the wheel bearings due to brinnelling from the hammer blows.
I wondered about this after absolutely WAILING on a front unit bearing in an '02 CTD 4x4. I was even using a puller on the WMS flange while pushing against the stub shaft. I must have spent 2 hours beating on it in every conceivable way.

I figured we'd need a new wb assy but after all that it felt fine. I put it back in in the interest of getting the truck back on the road.....it hauls ~320 gals of water in the bed 6 to 10x per week....it's still going years later (shrug)

NOW I do realize a 3/4t truck wb is likely to tolerate more abuse than a passenger car, but I was still surprised the bearing didn't seem fazed....
 
A good point, I said stretched, meaning pushed to the point of elasticity, and meaning, “damaged”. I should’ve just said damaged.

Bolts are cheap.

I am still a bit baffled by tightening with a pipe, no measurement, and snapping off bolts, instead of using a torque wrench. High strength bolts, and safety critical fasteners, are the instances where torque wrenches are really needed.

Not a pipe extension and OMG tight, hoping for the best, and on occasion, encountering the worst.
Meh, I'm just glad to hear I'm not the only one who does dumb stuff, er I mean dumb stuff when I'm tired....yeah yeah that's it

I think it's cool OP fessed up to his mistake. He already acknowledged he was tired/not thinking and it was dumb

It happens. He's owning it and he's fixing it. After this hassle I bet he's far less likely to repeat the mistake
 
I once did the front brakes on an F150 or expedition I don't remember exactly, the dealer did them last time but for some reason the R/side was wearing out quickly. The dealer replaced the rotor on the L/side but said frig it on the R. When I tried to remove it I found out why.
BFH, big air hammer, smoke wrench, nothing happening, hardened bolts through the caliper holes to push it off, no go, After an hour I called it quits and came back later with a new idea, a sawzsall, where the caliper mounts there is an opening in the backing plate/dust shield so I cut through the rotor all the way down to the hub but not through it then split it with an air chisel.

Holy cow it was like welded on with rust, the hub was also rotten so I changed that too.
 
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