I am having a problem with my 48 chevy. I have 11" disk up front and drum in the rear. I have got all the air out of the lines but my problem is that my disk hit first way before the rears do. I have read about every thread on this, and still cant solve it. My power unit is on the firewall. Is there any type of valves that i need to install to solve this problem.. I really need some help.