bad brake booster?? Options

[Valo666]

So for the last little while ive been trying to figure out what is up with my brakes..i put new pads and rotors on, brake lines, replaced 2 calipers..pretty much did an entire over haul of the system over the last 6 or 7 months and my pedal is still kinda mushy. Ive found that when i start my car up the brakes grab alot better than when i run it for say 5 min. Also when im at stop lights my pedal is hard, but i can still keep pushing it. Also if i keep pushing it harder and harder, my idel starts to decrease. So say its regularly at 900RPM, it will drop about 200RPM easily and every time i push hard. Could this be caused by a bad brake booster?? or vacuume leak?? Im gonna get my steering and suspention teacher to take it out for a spin later on in the week, but im just curious if thats what it might be. Also can u buy just the booster sepertaly from the master cylinder?

[Valo666]

bump

[playr158]

vacuum leak could definitely be an issue..

but i have a brake booster sittin on my shelf i could ship up to crazy cheap

[Valo666]

ill double check the vacuum lines first..but if not ill pm u and we can talk about it.