I've been having a problem with my brakes, they started making noise and sometimes when I pressed the brake it went all the way down, I thought I needed new breaks and I bought new ones and replaced them. My old brakes were still pretty good, but I went ahead and changed them. Anyway this was 3 or 4 weeks ago and my brakes have been working alright until yesterday when my brake went all the way down again and the car barely stopped, shortly after that my ABS light came on. What could be the problem here?

 

2 different problems; The sinking brake pedal sounds like the Master Cylinder is bypassing, or there is air trapped in the system; often times there will be fluid seeping at the base of the master onto the booster when the master goes bad.
The ABS problem ....you need to get the code.