King of drill bits :

https://www.wurthusa.com/Abrasives-C...s/p/0624930025

Not cheap I grant you, but hugely effective.
I've also been using a superb tapping grease/compound when drilling bolts out, and it keeps drill bits waaaaay sharper, waaaaay longer (but I can't remember what make it is ...)

 

Replace bolts with studs: https://tarett.com/collections/break...liper-stud-kit. Also prevent eventual stripping of threads in the upright.

 

Clue, Follow De Jeeper's guidance. Drill it out. And most critically, "you only need to get (drill) to the base of the head." You don't need to drill any deeper. Pop the head of the bolt off and then pull off the caliper. That'll give you an inch or more of bolt to grab on to with vise-type grips. If you are uncertain, look at one of the bolts you got out and how you might drill out the head. You are only drilling enough to pop the head off.

 

So, why do you not want to try an EZOUT bolt extractor?

 

U have to drill a hole anyways so why not just remove the head and get very good access to the rest of the bolt. Also I wouldnt want to risk breaking the easy out in the bolt and making the problem worse.

Most likely the bolt head is frozen in the caliper and thats why it stripped out and no easy out will be strong enough to break it free.

 

Is this in a front or rear caliper? If front you can remove the hub assy and bring it to a machine shop.

 

Saw this:

 

I had the issue to the point that the head snapped...
I used that :
Worked very well.
However the thread in the hub came with the bolt so I had to drill and use an helicoil after.

 

I hate ez out's. A buddy found a set in his basement and asked if I wanted them. I told him, "clean them up carefully, oil them nicely, and give then to someone you don't like".

 

Thanks for all the advice. For the sake of posterity and anyone reading in the future I figured I should let you know how the story ended.

I tried hammering in a 12mm torx. Did nothing except make things worse.

Then tried to hammer in a larger 11mm hex bit. Thought I had wedged it in there pretty good. Again the caliper bolt was so immovable it did nothing and just spun.

Finally I gave up and drilled. Basic cobalt bits. It was much easier than I expected, doubt I even had to go 1/2 inch deep. A 5/16 or 3/8 inch bit took off the head (I forget now which one iff to was). 10 minutes max probably more like 5

After getting the caliper off I sprayed on some atf/acetone mix. Mind you I had been soaking the caliper bolt in this and kroil earlier, but the bolt threads looked bone dry. Now that I had access to the hub I figured I would let it sit overnight.

10 minutes later I decided to use the wrench to get a sense of what I might be in for tomorrow. Holy smokes. Even with just 10 minutes, now that the penetrating oil was actually on the threads the bolt actually seemed like it might move. 5 minutes later it came out like it was nothing. I inspected and tried one of my other caliper bolts… threads look clean and undamaged in hub.

Highly appreciative of the input. Hand drill off bolt head and penetrating oil / pipe wrench on exposed bolt has my thumbs up as easy peasy recommended procedure in this circumstance.

 

First glad you got it out. Porsche recommends using new caliper bolts each time because of galvanic corrosion between the steel bolts and aluminum knuckle. Same reason they want spark plugs changed ever four years. They are not stretch or torque to yield. If you track or Xcross installing brake caliper studs is the only way to go. Too easy to damage the aluminum threads.

 

Love it when a plan comes together.

 

I have had 1 bolt freeze on me and went through the same process.

I find some cars the calipers are over-torqued.

I always recommend using hand tools only when working with these bolts (or any iron bolt in an aluminum fixture).

--Aaron

 

All good advice. Another thing I noticed is that my socket did not fully engage the bolt head; the flange of the socket hit the caliper before it could go fully in. I had to get inventive in order to ensure full contact.