my dad has a 99 dodge ram 3/4t w/ cummins and hydroboost . .. and a sticking brake pedal. pedal comes up very slowly, leaving the brake light on if you dont pull the pedal up with the top of your foot. if you push the pedal hard enough at a stoplight and let go, it will actually hold the truck still for a second or two. my dad just had the rear calipers replaced a month or two ago. the problem started about two weeks ago, went right back to the same shop, put new front calipers on and a new master cylinder. didnt fix the problem. any ideas?