A "bleeder valve" is a small device used to release unwanted pressure or air from a closed system. It helps maintain the desired pressure level by letting out any excess air or fluid.
Sentences with «bleeder valve»
It has an air bleeder valve that helps you to quickly eliminate air pockets. (geekwrapped.com)
It looks like the small bleeder valve on the bottom left of the radiator is leaking. (mechanics.stackexchange.com)
@rob - I assume if you open a rear bleeder valve you are getting fluid when you push the pedal. (mechanics.stackexchange.com)