Hi!
I've just changed my brake fluid on a gsr, now my brake pedal sinks slowly with the car started. If the car's off, the pedal don't sink! I've checked and there is no leaks! Im wondering if my BMC is leaking internally or the booster is dead?! or could it be just bubbles in the lines?
Thank you!

 

did you bench bleed the MC
then flush the whole sytem??

do those first

you def have air

 

pedal sinking is more like leaking MC seal... but as mentioned, bench bleed the MC... BUT, if you didn't replace it... you shouldn't need to.

 

I have the same problem on my 1990 Integra GS but its intermittent the brake petal will slowly sink to the firewall but not all the time and there aren't any leaks and the reservoir
stays full anyone know if its the master cylinder, the booster or the vacuum check valve?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SiR-G96 &raquo;</TD></TR><TR><TD CLASS="quote">Hi!
I've just changed my brake fluid on a gsr, now my brake pedal sinks slowly with the car started. If the car's off, the pedal don't sink! I've checked and there is no leaks! Im wondering if my BMC is leaking internally or the booster is dead?! or could it be just bubbles in the lines?
Thank you!</TD></TR></TABLE>

I have the same problem on my gsr. At first I thought I got air in the system so I bleed the whole thing again. Same problem, so I knew it wasn't air. I pretty sure it's the MC, I bought a rebuilt one but havn't found the time to install it.

 

Thanks everyone!
I found the problem!
MC is leaking internally! Pedal sinks less or non when cold, and sinks faster when hot. Because MC metal houseing expand more than the rubber piston seal!
My MC died - Internal Bleeding!
Thanks again

 

Cool, I bought my master cylinder rebuilt from autozone.com with a lifetime warranty for $90.

 

If you bled the system, replace the MC and call it a day.