I had the old style hex bolts. 7 came off but one was so stubborn I now have an inside strip (the interior hex “socket” on the head of the bolt is now rounded sufficiently my hex bit rotates).

What now? Any suggestions?

 

Easy Out Bolt Extractor.

 

Find a torx bit that is just just too big to fit and hammer that in.

 

^^ THIS ^^

 

Yes this.
If it doesn't work drill the head off. Remove the caliper. Unscrew the remnants with a pipe wrench.

 

Or saw it off?

 

that is not possible as the bolt is recessed in a countersink on the caliper.

i tired an M12 torx but it didn’t bite and I think made things worse.

wondering about using propane to weld something to the bolt before going the drill route?

 

Drill it. Just get a few new drill bits. The only way u will be able to get in there and weld anything is gonna be with a tig.

 

You should replace caliper bolts with new whenever they are pulled. That's probably a bit ****, but every other time is probably good.

Also, a quality socket for high-torque bolts is not a bad idea.

 

I have the same situation with a header bolt I snapped off recently. Just the head came off but not sure how I can get the rest out without having a nut head welded onto it.....which means bringing it in to a service place......for now I can run it the way it is but will eventually need to fix.

 

carbide bits? I tried another one of the bolts in a vise to see what I was getting myself into and with titanium it seemed like it was gonna be very challenging. Any other tips?

 

I think Porsche might even recommend new caliper bolts when they are removed and not to reuse them.

 

i would start with a 3/16 bit then 1/4, 5/16, 3/8, 7/16, 1/2. U get the idea...step it up slowly. U only have to go in about a 1/2' to get to the base of the head. Control the drill speed and use oil for lube. It takes some patients but its works.

Caliper bolts r just regular steel not titanium. I use cobalt drill bits.....carbide is for masonary.

 

Don't use carbide in a hand drill. It's very tough and very brittle. Like Aaron said start small with a 1/8th and step it up from there in small increments. The bolts are hard, they aren't excessively hard.
Don't use harbor freight drills, they are not sharpened correctly. Or the Amazon chinese no-name brands. Get a good set of drill bits from a US company and use those.

 

That's because they're elastic/stretch bolts.
Use off the shelf cap head bolts (grade 10.9 or 12.9) with a new/decent driver piece, and those suckers will outlast every set of pads and rotors you can ever throw at them. Just make sure you use aluminium paste on the threads and reduce the torque setting accordingly.