I purchased a disc to disc valve from Master Power Brakes for My 1970 Chevelle.....I put the lines on stared bleeding the rear brakes and getting nowhere!!!!!! I then look in the front and i see a little puddle of fluid and come to see that the valve ....it is leaking from the front main seal...I called and they told me they would send me a new nut screw..i checked the threads and everything was fine......they told me to put teflon...on it...which i think is bull....since it is new.....Where else can i purchase one that wont leak or what car can i take one of that would work ....thanx Jerry