I'm building an off-road wheelchair and I'm using a 1" go kart axle in the rear. I'm using downhill mountain bike brakes in the front pushed by a brembo master cylinder. I was planning on integrating a caliper into that brake system but it seems there will be challenges with that specifically the fact that the bicycle brakes use mineral oil and the kart brakes use DOT fluid. Also I'm afraid the front brakes are more sensitive and will come on harder than the rear. So I'm planning on using a separate master cylinder for the rear brake now. My question is about these master cylinders with two lines coming out of them. Are these lines connected hydraulically? Meaning if one of the lines breaks is pressure lost in the other as well? I also have a question about these 1 or 2 line brake calipers. Do the one line calipers tend to rub on the rotor on the non piston side? Would hate to hear rubbing of the rotor when the brake is supposed to be disengaged.