The brakes on my 97 2 door suck. I read that you need 10lbs of residual pressure on the rear drums, but I took a gamble and bought a gmt800 master cylinder without knowing if it had the valve (part number Dorman M630031) pedal feels better, but still not right. Today I discovered my back brakes were barely working, if at all. Takes about 3/4 second of an empty hub slowing down, so my front brakes are doing all the work. Don’t know if this was a problem before I changed the mc. Are all the guys that do this upgrade effectively deleting their back brakes? I don’t understand how the topic of residual valves and pressure is ignored. I know the 05-06 1/2 tons had rear drums, but couldn’t find the right master cylinder anywhere. What’s the deal?