'96 Dodge Stratus Parking Brake Repair

This car won't pass inspection because the emergency brake won't stay
engaged when you pull up on the handle. The thumb release stays depressed
and won't push back out. I've got the console out and the rubber covering
off. There appears to be a thin rod with a spring around it that feeds down
through the handle. I can take a screwdriver and force the rod forward
toward the release button when engaged, and it will catch the gear and stay
up. But when I depress the button to release the brake, it stays depressed.
I squirted WD40 over the moving parts thinking maybe the kids had spilled a
soft drink in there but it hasn't helped. I'm now thinking the spring has
gotten worn and no longer pushes the release button out with the force
required to make it work properly. Has anyone fixed one of these before who
can shed some light on this?