parking brake pedal

the parking brake pedal on my 1998 chevy s10 wont stay down therefore my brake doesnt work.any ideas on how to repair or replace.the cable is in place but it seems to be on the pedal mechanism.ill appreciate any help

glad I'm not the only one with that problem in my '98! problem mine has is the release lever attached to the release cabel is not fully retracting, almost like a bad spring on it. luberd it up and still nogo. replaceing the PB pedal assy is not the funnest job. could check it out and put a spring on it....prolly find a decent one at a local hardware store.