I'm not the most mechanically inclined person so here goes.... I just replaced my master cylinder in my 4KQ and the brakes bleed fine when the car is off but when i turn it on, all the pressure goes away. Is there a vacuum leak somewhere? I'm going to replace some hoses and plug some holes tommrow and hope that'll do it but i'm not sure. If anyone has basic info on this subject any help would be appreciated. Thanks!