disk brake caliber with parking brake auto adjust

[zagrot]

i have an issue with the self adjustment feature of disk brake calipers with the integrated parking brake. here is the story: today i replaced both rear calipers on a friend's audi a6 and the calipers refused to self adjust until i screwed their pistons back into the bore (they were new units and delivered with the piston fully retracted). one would not stay near the brake pads after applying and releasing the brakes, it would retract about 1/8"- 3/16" causing a very long pedal throw before the brakes took up and became firm. the other jammed and i had to pry the caliper to get enough play to remove it and screw the piston back into the bore. after giving both of the pistons a good screwing (ha!) both worked fine (speaking of which i wish auto designers would pick a standard pattern for the piston tool and stick with it, the infamous "cube tool" doesn't have a suitable set of projections to match up with any car that i've used it on).

anyway, the job is mostly over and the reason for this thread is this: one of the new calibers had defective threads in the brake hose connection and it just would not seal (could see the impression left in the sealing area, and it did not continue all of the way around), so i have to do half of the job over again after the defective caliber is traded for another, so should i just put the new caliper on and see if the whole thing plays out as it did today, or should i just give the piston a few turns and be done with the installation the *first* time (i hate removing stuff i just put on)? normally i would have taken one apart to get a look at the inner workings to answer the question myself, but the owner is taking care of furnishing the parts and the job ran way longer than i expected (also repalced the parking brake cables, if anyone ever mentions "quattro" and "brake cables" again in the same sentence i'm leaving in a hurry).