stuck brakes

[survyor2]

I'm trying to narrow down a problem I'm having with my brakes. I recently redid my engine bay so the brake boost and master cylinder were removed. Everything was reinstalled including a line lock device. The brakes were bleed and rebleed. I had some problems bleeding through the abs actuator but I rebleed them for the fourth time today and the fluid runs smooth on all four corners. When I start the car the brakes are applied without me touching the pedal. I see the pedal sink. I can pull the pedal back up with my foot but the pedal will fall again and the brakes are acting like its me hitting the pedal. Its almost as if the brake booster is working too well or the master cylinder isn't apply enough opposing force on the rod of the brake booster. I believe the line lock device isn't the problem because everything bleed fine. With the engine off, the system seems to work more normal. The brakes don't stick, but the pedal seems to take a long time to bounce back to its resting position.

So bad master cylinder or brake booster?

Thanks,
Dennis

 

[AbsoluteSpeed]

Did you prime the master cylinder before installing it? Are you loosing any fluid?

 

[survyor2]

No fluid lose. None at all. I originally did bench bleed this master cylinder when I first got it but I did not rebleed it after i remove and reinstalled it. I bleed the system at each caliper and it bleeds fine.

 

[tlo86]

mityvac time

 

[survyor2]

After read this and learning more about how brake boosters work, I'm 99% sure I have a bad booster.

http://www.agcoauto.com/content/news/p2_articleid/129

My main problem is I have a CF wrapped booster. I prefer not to replace it. I want to rebuild it. I found a local company that rebuilds them for $129, which is perfect. However they cannot get a rebuild kit. Toyota does not make a rebuild kit. Does anyone know of a brake booster rebuild kit I can find online?

Thanks,
Dennis

 

[hvyman]

aaron at driftmotion rebuilds them i believe.

It also looks like the cf is over the area where the master bolts up. Might be causing some leak issues.

 

[tlo86]

i wouldnt mind learning how to rebuild them. theres a guy down the street from me that rebuilds the rarest of boosters in minutes it cant be that difficult heh

 

[survyor2]

i wouldnt mind learning how to rebuild them. theres a guy down the street from me that rebuilds the rarest of boosters in minutes it cant be that difficult heh

I would think the hardest part would be opening them and then sealing them.

 

[survyor2]

aaron at driftmotion rebuilds them i believe.

You are correct. Thank you! $159 I'll send it out next week and hope they don't have any issues with the CF.

 

[Poodles]

Could have simply been a bad adjustment of the booster. http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BR&P=21

 

[slowma70]

please update us when you get it back..