I have a 99 suburban 2500 454 4x4 and I am going thru front brake pads about every 10k miles. The rear brake shoes are maybe 1/2 worn with 60k miles on them. The truck has an electroncally controlled proportioning valve. Is there a way to adjust this? i have a factory service manual which doesnt say anything about adjusting it. The truck has a hard time coming to a complete stop, sometimes with smoking front brakes. Just replaced the front rotors , pads and had to install a new hydroboost, helped but didnt fix the problem. I am thinking about going with a rear disc setup if it will function with the proportioning valve, abs and the rest of the truck-- anyone know of one ?