I get on my car and my brakes feel fine nice an firm, but sometimes when im going down the road at about 40mph then i press the clutch then brakes to slow down my brakes feel so soft they go all the way down i have to quickly pump 2 twice then it gets nice a firm, this is starting to scare me i dont know when its going to happen but it happens. i have a 90crx dx with a b16. is my MC going bad or do i need to bleed my brakes more.

 

Thats a bad MC symptom 100% - get on the brakes and then ur foot sinks down. That or you either you need to bleed your brakes.
You say "do i need to bleed my brakes more" Well, did you already bleed them?

Vaccum booster is the opposite - a very stiff pedal.

 

my brakes did the same thing when my mc went out. make sure you know how to replace it correctly if you plan on doing it.

 

i bleed them 3 times each side, if i get the problem again, well that will give me the excuze to buy an EX mc 15/16 yeah