Ah, I've been watching this conversation and was sure Radare was probably right, but didn't see your mistake until just now. Your thought here would be right if it were a floating caliper like most cars have these days. With a floating caliper, there is a range of distance that the caliper can be located based on the center of the rotor and still work correctly. When the system is pressurized, the pistons will push the pads out until they contact the rotor. Because the caliper "floats" on slide pins, the pressure on one side being higher than the other because the caliper is off-center will force the caliper to move laterally until the caliper is centered, thus balancing the pressure.pdworak wrote:Even if it is 1 mm off, it really doesn't matter because the first time you apply the brakes, the 2 opposing pistons in the caliper will center themselves on the rotor and work just like normal afterwards. The only issues might be contact between the caliper and rotor or insufficient clearance on one side to get a new pad in, though I doubt 1 mm will make that much difference.
However, our calipers are fixed, not floating. The caliper cannot move laterally to center itself over the rotor. If it is not mounted dead center over the rotor, there will always be uneven pressure from the pistons to the rotor. When the system is pressurized, the pistons will push out unevenly (one side farther than the other) to make contact with the rotor. Because your foot is applying even pressure on the entire system, the pistons with the shorter reach will be pushing with a higher pressure. This is because they are trying to move as far as the other side due to the same pressure being applied to both sides, but the rotor is obstructing them from travelling any further. In a floating caliper setup, that is what would make the caliper move laterally to even the pressure. In a fixed system, the caliper can't move, so the pressure will never equalize.
When the pressure is released, the pistons will try to retract evenly. However, the one side will likely drag because it would need to move farther (deeper into the caliper) than the other side to release because the caliper isn't centered over the rotor. They will still work, but the uneven pressure will generate uneven heat, and be more likely to drag (creating constant heat), both of which will wear pads out faster and unevenly, and make it more likely to warp the rotor.