Hex Socket Head Cap Screw

What a pain! / What a nuisance! / This is so frustrating!

Today I wanted to replace my brake discs, and of course, I immediately ran into a problem.

It's the rear brake of my Polo 9N.
Specifically, I rotated the 8mm Allen head screw (position 13 in the picture) that secures the brake caliper. This screw is normally tightened to 80Nm.
The frustrating thing is that I can't even get it to work with a drill. However, I can make it work with a Dremel.

Do you have a way to loosen the screw? Would it work if I simply grind off the head?

http://home.arcor.de/chris_kern/Bremse.JPG

Insert a suitable Torx socket (or slightly larger) into the rounded opening and hammer it in. Then, loosen the screw. Before doing so, apply rust remover to the screw and tap the head of the screw with a hammer to ensure it comes loose. You only have one attempt.

Forget about using the Dremel! Just use a slightly larger multi-tooth extractor bit and hammer it into the stripped hex socket. By hammering it in, you'll release some of the screw's tension, and then, if you can get a good ratchet on it without it slipping, you'll be able to remove the screw more easily.

Okay, and if I mess this up, I guess I'll have to resort to using a Dremel, or what do you guys think?

'Getting to that position is really a pain; I'm not sure if I can fit either a Torx or a star-shaped screwdriver in there.'

Hello.
Remove the brake caliper and, from the front (outside), carefully center the drill bit on the screw. Then, drill through the screw to the depth of the bracket using the core diameter of the thread. After that, the screw should come loose without any problems. However, before you do this, purchase a replacement screw or make sure you know what thread size to expect. The threads should be re-cut. When installing, apply plenty of grease to the screw.
But what is the mileage on the brake discs? Or is an upgrade necessary?

Best regards, Robert.

Unfortunately, I can't drill there because I can't reach it; I could barely get the ratchet in there.

My brake discs have a mileage of 70,000 km, but I want to install slotted brake discs from Zimmermann on the front and rear, because my braking performance in the rain is absolutely terrible.

Hello.
Can't you just drill the head off from the back using an angle drill? If you're already replacing the rotors anyway, check if the screws are outside the outer diameter of the hub. If they are, use an angle grinder to cut off the interfering part of the rotor, and then follow plan A as mentioned before. Alternatively, you can unscrew the entire axle and swing it out of the carrier with the brake rotor in the correct position.

Best regards, Robert.

As I said, I don't think I can get there with a right-angle drill.

Cutting a piece out of the disc would be a possible solution.

But wouldn't it be easy to simply cut off the head with my great Dremel tool, which also allows you to attach a flexible cutting disc? Or why are you so against using a Dremel?

Good evening again.
I'm afraid you'll be working on that for a very long time. I have a Bosch angle grinder, and in cases like this, I use a carbide cutter with a diameter of 6mm. It takes about 10-12 minutes to remove material from a head like that. And it's a messy job with those extremely fine chips – you absolutely need safety glasses. You're unlikely to get much done with sanding belts or similar methods. The stated power consumption, from 600 watts to an estimated 35 watts, gives you a rough idea of the work involved.

Keep us updated.

robert