88' Firebird 2.8L MPFI v6

I bleeded the brakes several times, gravity method, pump method, and changed both front calipers and brake pads figuring it was sticky calipers, front rotors are in good condition front and back of them, good front brake hoses steady flow of brake fluid passing through, back brakes are in good condition, drums were adjusted by me, also reversed to adjust...really doesnt seem to work but do anyway, also checked for broken springs, etc, nothing, drums are good as we'll. got good fresh brake fluid ( Dot 3 ) and nice tight seal on reservior, power booster has a good vacuum hose attached as we'll as a good check valve, as i brake the pedal gets nice and stiff but with little stoping power went from 0-30 stoped and went about 7-10 FT before actually stoping...for right now ive been allowing more following distance and pumping my brakes to allow it to stop easier, when i slowly press the brakes to slow the car down let's say from 35 to 25 it works like a charm...not sure why such weak stopping power, the master cylinder moves up and down as you pump the brakes is that normal? and do you think air could be in my master cylinder causing this?

 

Anyone?

 

A question and then a comment. What happens when you apply firm and constant pressure? If it slowly goes down, you have seal issue in the master. I know you say the rotors and drums are ok, but: when I've had firm pedal and poor braking, (esp. with A and F bodies) the things have been glazed. Fix the front first as that's where the vast majority of your braking power should be coming from. Just don't let the rear pass the front when you first get them working. No, I don't think the M/C should be moving much when the brakes are applied. One more thing: if you are pumping the brake, does that mean the pedal comes up with a couple of pumps like when there's air in the system? or do you mean you are modulating the breaks to prevent lockup?

 

Going back to your previous post when your brakes started acting up, you problem was your power brake booster was not working right due to wrong amount of vaccum because your engine was running crappy. Have you fixed this? Plug the booster line on the intake side and see if there is any difference. If not your brake booster is bad or you have a vaccum leak.

 

To test booster for bad diaphragm, or lack of function: With car off, pump pedal until it becomes hard. With pressure held on pedal, start vehicle. Pedal should go most of the way down, like you are braking, then firm up.

 

engine is running better now (fix code 33&34 it was the MAF wires they were to expanded), so are the brakes but not what they should be like, it still sometimes rolls to a stop.