This is driving me crazy! Ive always hated working on brakes, since Ive never had good luck with fixing problems with brakes. Im thinking, however, I might have a bad brake MC. When I press firmly on the brakes, it holds pressure for a long time, so if Im sitting at a light its fine. When I gradually apply pressure to the brakes for a slow stop it bleeds off and goes to the floor. When I did my search I didnt find anyone who had a similar problem, but the consensus was faulty mc's on a lot of the problems with spongy or no brake problems. I dont think its air because Ive bled it until it was dead. Ive played with the LSPV and I believe its working fine. Ive always had brake problems since getting the yota, I replaced the mc with a used supra mc and the problem got better, but still has an issue. What Im thinking is happening, is the fluid is bleeding from one chamber to the other, if I press the brakes firmly it ballons the seal out making a better seal then gently applying the brakes. Its not leaking anywhere that I can see, the rear brakes are adjusted correctly and the fronts have new rotors and pads. I dont know... Sorry for the novel.

 

The only thing I can think of is a bad seal in the MC like you said, and you stated you replaced your old one with a used one also. It might be best to replace with a new one and make sure your front calipers and rear cylinders are not leaking one more time. I hope this helps

 

sounds like a failed brake master cylinder. Go ahead and get a new one, but make sure it's ASCO/Aisin brand. They're OEM without the Toyota price tag.

 

Well I think I got it fixed, I did replace the master. The first one I bought band new from Napa and out of the box it leaked. So I took it back and another one it seems to be fine. I dont think its Aisin though, so I hope it holds up. I already purchased and installed it before I got the last reply. Thanks for the help. The good news is its all new fluid in the system. Now for TC gears and lockers of some kind, leaning toward supra LSD's. I know there not lockers but theyll get me by until I can get a elocker.