Next time the problem occurs, loosen the master cylinder mounting nuts two turns. If the brakes release, the booster push rod could be out of adjustment. If they don't release, loosen the two steel lines. If the brakes release now, the seals in the master cylinder are swollen. Suspect the brake fluid is contaminated with a petroleum product. The only proper repair is to replace everything with rubber, including seals and o-rings, and to flush and dry all the steel lines. One new part will become contaminated from the other parts if they aren't all replaced at the same time. You will also notice the rubber seals under the caps of the master cylinder are ballooned up and mushy.
If these things don't help, see if one wheel releases if you open a bleeder screw. If it does, look for a metal bracket holding the center of the brake hose. There may be rust buildup inside the crimp around the hose that is constricting it. Just peel that metal bracket open a little with a channel lock pliers.
Saturday, January 2nd, 2010 AT 4:32 AM