hello sl6 sages- this may be a job for the doctor. back in 91 i installed rebuilt front brake calipers and hoses and pads in my 76 feather duster. been working fine since. noticed last week when i replaced control arm bushings that the right calipers piston was stuck which is how these items usually crap out. i replaced the caliperand pads,compressed the other caliper to put in new disc pads and bled the new caliper. everything worked fine. two days later the brake pressure light came on indicating unbalanced pressure ie air in thesystem. i rebled the new caliper and ok. twodays later the same thing. i then rebled the new caliper at the brake hose connection to the caliper instead of the bleed screw - no change . then i bled the other caliper andthe problemis gone- no brake light on. i never opened the other caliper when i replaced theright one. how can air get intothat old one. a local sage (chrysler mechanic since fluid drive in 49)told me it wasnt an air problem,but different static pressure in the unopened left caliper compared to the new right one which i corrected by the last bleed on the old caliper. this confuses me since i thought the front brake hydraulic system equalized automatically as long as the air was bled out. does one side of the system hold residual pressure? looking forward to the correct analysis of this riddle from sharper sages than me. thanks tons callpaladin

At the job, I have replaced many calipers, wheel cylinders, lines, etc., and
often it depends how long the line is left open to "drip" bleed. If you take the old caliper off then run to the parts store to exchange the old one, and let the M/C run dry, of course you will end up with air in the other side. If, on the other hand, you have the replacement on hand and change it fast enuf to not let the M/C run dry, I have often been successful in bleeding only the replaced part without having to bleed the one on the other side.

hello volaredon- thank you for your reply. i realize that if the right side line was left open while i went and picked up a replacement caliper which i did(about 1 hour), the open line would drip bleed out of the hose. some fluid was in a cup which i put the end of the hose in. when i put the new one on the right side, i opened the master cylinder and the rear tank of it was still almost full- that is it had not bled dry to the supply hole at the bottom of the tank . my q is since the supply hole at the bottom of the mc remained submerged, could air still have gotten into the left side caliper which remained closed?i think the only way that could have happened was if air went from the open right hose to the left closed hose- i am not sure if that can happen and invite your expert opinion. when i bled the left side the problem was solved. what do you think about theoriginal theory of the static pressure imbalance on the left side having tobe bled out or relieved. thanks tons for your input. regards callpaladin