Okay, how do you tell if a master cylinder is going out? Got my brakes bled, but the pedal is still spongy and when I jam on the brakes, the truck just slows down, no way in hell they would ever lock up. The master was sitting for about a year or more . I bled them the normal way pumping and cracking the bleeders while holding the pedal down. Cracked the lines at th master first to bleed any air trapped in there. Oh yeah...90K5, 1 tons, rear disk. I am gonna try pressure bleeding them next with one of those home made garden sprayer bleeders. Maybe that will help out more. On a 90, is the the front resevoir for the front brakes and rear for the rear or? Stupid question, but on searching, I came across some saying the rear was for front and front was for rear so now I am confused Also, seems most people leave that little pin in the combo valve alone, so I will do the same when bleeding. Not sure what that does to aid in bleeding the system. Now, if I do get another master cylinder, should I get a booster as well? With searching I've seen people upgrading to a 3/4T master cylinder or JB7. Will they use the same push rod as my 1/2T? Do I get the 3/4T booster as well? Thanks.