I took my car to get the brakes bled today (it was there for other work also) and they told me the system wasn't holding the pressure. No fluid leaks, but the pressure didn't hold.

Did your upgrade include a Master Cylinder too? Maybe a bad seal in there.

Yeah, I did a brand new s10 master (I believe it was s10, it's been awhile). It seems like since there is no fluid leaking anywhere it could be passing by some seals inside.

[This message has been edited by sactodreamer (edited 03-09-2015).]

I did this upgrade last summer. I used a 2000 Cadillac Escalade master cylinder on my swap. I cannot find the original posting here, but I just checked my parts list. It was cheaper and it was an aluminum body so I don't need to worry about rust and is look original.