how true?
well, I dont want to come off like a professor of hydraulics, but, all the parts must be perfectly squared to the rotor. the rotor must spin perfectly true, with no more that .003 runout. the caliper must pull into the rotor SQUARE.
the frt. whell must not have any bearing play, side to side or lateraly. if you can get a good holding pressure with the c clamp installed, its not the hydraulics that is at fualt, but the mounting, tapered friction material, or a rotor run out of some nature. class dismissed.;)
Rick