inconsistant peddle

ok so we did the MPB disc conversion on the duster and replaced everything, the problem is even after bench bleeding the master and countless bleeding of the brakes (rear right, rear left, front right, front left) the brake warning light keeps coming on intermitantly and sometimes will stay off until you push very hard on the peddle and it will come on again also, if you pump the brakes a few times then depress the peddle the light wont come on even if you push as hard as possible but when you let up and try it again the light will come back on after you depress the peddle say half way or so....

so is this a master cylinder problem as this is a rebuilt unit that we have had to change out bc the one in the kit leak through the real seals, we are at a loss to figure this one out because we are no experts anyways thanks in advance!
Author: admin