I just put rear pads and rotors on my 97 Expy. The fluid in the master cylinder was black so I bled all 4 wheels and got clean fluid in the system. Prior to this I had a good pedal. Now my pedal feels soft for the first 1/3 of the travel but the brakes do activate during that 1/3. After that 1/3 the pedal is nice and firm and the brakes feel fine. Then when I release the brakes it feels like an air brake system where the brakes don't release right away. It just has an odd pedal feel. Could I have flushed some dirt into the proportioning valve? I'll try rebleeding it tonight. Is there such a thing as back bleeding and hopefully get the dirt out? Thanks.

 

Well the brakes are fine as of last night. I didn't have to bleed them again. If it was something that dislodged that caused a problem it's gone now.