Caliper bolts WILL NOT budge

[turbid2wenty]

Howdy folks!

Trying to perform a front brake/rotor service on my B7 S4. Seems to be the worst luck I've had in a while. The set screw is clearly rusted out, and will likely have to be drilled out.

I've not been able to get the caliper bolts to budge. I don't seem to be able to fit an impact driver behind. I've heard a mix of acetone and ATF works wonders. Do I need a longer breaker bar, or just more muscle?

[Tim Brown]

My experience (on a SAAB) was that you need a 24" breaker bar, and when you apply force (big arms would have served me well) the bolts give way VERRRY slowly, almost imperceptibly so. On one, i actually stood on the bar. enlist a heavy lifter to help if you are not one, or use a pipe cheater slipped over the bolt. The more common 18" bar will not do it, and the 24" is nice to keep in the trunk with the right socket on it to break loose wheel/tire bolts that have been put on with a monster airgun and have then frozen on place. For the set screw, if the torx socket has already been stripped away, get a screw extractor and drill, but not enough to wreck the threads. If the torx pattern is still there, use powrblaster first, give it some time. Possibly an impact driver with a torx bit (the kind that is used to drive screws, not the big air hammer).