Bleeding brakes on hydroboost

[BuickTV6]

Hey guys, I ran into some majoring brake problems with my Buick a few days ago. Went and hit the brakes, and nothing there, almost got myself into a good accident. Brakes went right to the floor, and as of right now, i barely have brakes, unless i pump the hell outta the pedal. Even at a stop. It'll stop me, and i'll feel the pedal go right to the floor and i'll start moving until i pump them. I did the whole front end with new pads, calipers, rotors, and I am in the process of putting on new drums, shoes, and wheel cylinders. Also going to change the master cylinder and i have a few questions. How hard is it to change out the master cylinder on hrdroboost? I heard something about a spring in it that can cause damage? Can someone tell me whats involved with this? Also, since the system only has pressure when the car is running, does that mean I have to have the car running in order to bleed all the brakes? if anyone can help me with this, it would be much appreiated..

 

[BuickTV6]

TTT

Someone? Anyone!?

 

[turbogimp]

most likley a new master cylinder will fix your problem. make sure you bench bleed the new master cylinder. its simple remove the brake lines from the old then remove the 2 nuts from booster and pull it apart. install in reverse order then bleed the system and your done. to bleed there are two ways to do it. the easy way is to gravity bleed you only need one person but, it requires alot of time. ENGINE NOT RUNNING. to do this make sure the master cylinder is filled with fluid then open all of the bleeder valves and let it sit just check the brake fluid level every 1/2 hour to 1 hour to make sure that you dont run out of fluid in the master cylinder. then close all of the bleeder valves in about 4-5 hours. or the pumping method you need two people to do. ENGINE NOT RUNNING. starting from the farthest from the master cylinder have some one pump the brakes like 5 times and then hold it. open the bleeder valve let fluid drain out, close then start again. do this until you have clean fresh fluid and dont see any air coming out. then do the rest. hope that helps