ok i was bleeding my brakes and there is pressure when i bleed it but when i start the car the brakes go straight to the floor. if i drive it the brakes hold but the pedal is all the way to the floor

i want to know if it is most likely the brakes master cylinder or the booster?

 

A good possibility is the M/C. I am currently debating myself whether to replace both at the same time.

I have the same problem as you with the pressure being there and once the car turns over the brake pedal goes to the floor but only after a while of applying pressure to them. It does help when i pump the brakes while I'm driving.

Have you re-bled the brakes? Checked for leaks?

 

A bad brake booster would not cause this problem.

My recommendation is that you rebleed the brakes as there is still likely some air trapped in the system. You also need to bleed each wheel in the correct order. Finally, I recommend that you purchase this inexpensive tool.

 

That is a great tool, I have the hand vacuum pump version, works like a charm.

 

I use an empty container and a hose, does the same thing since I'm cheap.

 

yes i did re-bleed the brakes 2 times and still having the same problem. i bled each wheel and the M/C and there are no leaks and no air when i bleed it

well i guess i'll just change the M/C and see wat happens