Brake pedal low

Have a 79 c3.The problem is the brake pedal is too low and the car is not braking properly.Replaced the master cylinder and the problem still there.checked for leaks and none was found.I suspect the problem is in the calipers,how do i test the calipers?  

when you replaced the master.. did you bleed the entire brake system...  all 4 wheels...

pressure bled..  or just pedal bled.. or did you use one of the neat vacuum bleeders.. ?????

are any of your calipers leaking slightly???? wet spots around the pistons...

autozone has a good deal on reman calipers.. with sleeves..

have you replaced your brake hoses lately???

turning the last brake pad installation... did you have your rotors turned?????    

was there much ridge around the outside????

if there is a ridge on the outside of the rotor.. that indicates wear to the rotor faces... it is actually taper... the  outside of the wear area actually moves faster than the inside ... (in inches per second.. )   the outer edge is 11.750.. the wear section is an inch and a half wide..     so the outer most wear section goes...36.9 inches around the circle.. the inner most section at 10.25 inches goes 32.2 inches per revolution..

the calipers are set up for parallel ... the pads new pads are parallel.. if the rotors are tapered.. the pads will touch near the center... then the caliper pistons will have to bend in their bores to try to match the pads..  this gives you a soft pedal...

loose wheel bearings or warn wheel bearings will allow movement at the caliper.. and it will take extra pedal movement for the pistons to push the brake pads to straighten the rotor up  to its normal alignment with the caliper..  

Found the problem.In one of the front calipers,a small piece of the brake pads "lining" was missing.Had to install new pads, the caliper had to be replaced because of the angle taken by one of the pistons to compensate for the missing material.Those brake pads were almost new,weird.........