My Mazda has started to make a grinding, metal-on-metal sounding noise whenever I push in the clutch pedal. The RPMs also drop, sometimes stalling the engine. This happens only when the clutch pedal is pressed in, whether in gear or not. When I release the clutch pedal, the noise stops completely. I first suspected the clutch release bearing, and I replaced it as well as the pilot bearing, but it did not change the problem in any way.

My vehicle is a 1991 Mazda Protege LX. It has the 1.8 L DOHC and 5-speed manual transmission.

 

did you check fly wheel and pres plate when you did the bearing replacement?