First off i have replaced everything on the brake system besides the proportioning valve. I have bleed my brakes repeatedly time and time again and i still have a spongey feeling brake. the only thing left that i can think of haveing any real effect on the hydraulics part of the brake system is the proportioing valve. I have not found a price for one for my 91 explorer yet but from what i have read in other forums they all sound pretty expensive, so i was considering taking my proportiong valve off and by passing it to see if i can get a build up of pressure that way. I figured by running a line from the master cylinder down to where the proportioning valve was and then just adapting it to the line going to the rear brakes i may be able to at least get some kind of additional brake pressure then i had before. I would never consider driving the explorer this way but i am just trying to find out for sure if its the proportioning valve messing up or if i bought a new master cylinder that isnt working properly or what. Im very frustrated with this problem no matter what i try nothing seems to change the stiffness of the brakes. Well if anyone has any advise or ideas on how to determine exactly what is malfunctioning please let me know, also does anyone think the idea of bypassing the proporting valve will build up more pressure if it is the bad componant? Or am i just spinning my wheels here??? any help would be appreciated!!!!! by the way the exact yr& model is 91 explorer XLT 4wd with rear anti lock brakes,, if this help any