Wait, I don't understand, do you want to break the brake hose, or remove the caliper from the brake hose?
Why would you want to do either, unless your replacing the caliper.
There is another bolt on the caliper that holds the brake hose on the caliper. I find it's easier to have the caliper bolted to the bracket to break the brake bolt loose. I forget the size, I think it's 11mm. No need to tighten the brake caliper bolts to tight to break loose the brake line bolt.
If you do break the brake bolt and it's broke, it won't break the bank to buy a new bolt to repair the brakes. It's a speical bolt that allows brake fluid into the caliper. If it's broke for trying to break it loose, you gotta replace it or the brakes won't work
Couldn't resist.
Plus if you have 12mm bolts on the calipers, they've been replaced. The fronts are 13mm on the caliper and 15mm on the brackets and the rear is all 13mm or 13mm on the brackets and 15mm on the calipers
Also, don't lose the copper "O" gasket under the brake line hose on the caliper. If you don't put it on, the calipers will leak brake fluid