Have 98 blazer LT, brakes started getting spongy and losing pedal. Checked for leaks and found none but noticed air sound from booster was louder than normal. Changed booster and tried bleeding brakes but could get little fluid to right rear caliper off the bat. Same with the rest, also brake pedal is extremely high. Read about adjusting push rod on booster but was kinda unclear. Any advice on this would be appreciated. Forgot to ask if anyone thinks proportioning valve could be causing this and how to test it.

 

When you changed the booster did you use a new one? Did you disconnect the fluid lines at the master cylinder?

 

The booster came from a 96 blazer I have with transmission problems, it was good about a month ago when I drove it last, but I know how that goes too. And I did disconnect the lines from the MC. I will buy new parts but I want to be sure of the problem as they are kinda costly. Any advice on a fix or how to test for the faulty part is greatly appreciated. Thanks.

 

Take the MC out of the 96