I made all new Brake lines on the car, Bled everything perfect and when i started the car, turns out my Master Cylinder was leaking but perfect brake pressure other wise! SO i go and buy a new Master cylinder and install it. Now after having rebleed everything, it feels good when the car is off, But when its running the pedal goes down really easy about half way, then LOCKS the brakes basically.... I tested the Booster outside of the car, and it held Vaccum perfectly.
The car has a t2 engine in it, so the only thing i could think of is if the booster was hooked up to a wrong nipple...BUT the nipple its on, has vaccum at idle :S

Any ideas what this could be??

 

Did you benchbleed the new master cylinder properly?

 

yup.....no bubbles

 

Bump!

 

You have air in the lines/master- Keepy bleeding! Are you bleeding with the car running of off?

 

I was bleeding with the car running off..... I've never had problems doing it that way in the past, Have you noticed a difference when doing it with the car running? Would i be able to check if thats the problem by pumping the brakes while running, meaning that it would eventually build up pressure?
Thanks!!

 

If nothing else, take it to a brake shop and have them bleed them for you. Some of the better shops can use a "power bleeder" which works great. But since you have all new parts, this should be a sure fix...