Hey Guys,

I have a 97' 2 door tahoe, and I can't seem to get brake pressure to the wheels. I put a new EHCU and master cylynder on it, bled the master cylynder, bled the EHCU, and bled the rest of the brake system. There doesn't appear to be any air in the brake system, but I still can't get pressure on the pedal. With the truck off the pedal will get somewhat firm, but as soon as I start it and the vacuum booster kicks on I lose it. It's not throwing any ABS codes at me, so I am going on the assumption that the electronic end of the Kelsey-Hayes 4wal ABS system is fine. At this point I am truly at a loss. I'm not really sure what to try next. Any suggestions would be greatly appreciated.

Thanks,
Kevin

 

Maybe a bad vacuum booster?

 

You know I wondered about that, but in my experience (which is pretty limited when it comes to newer brake systems) a bad vacuume booster makes the break pedal really stiff not spongy.