How about the spring and the gasket, and the valve is on foot
The spiral pattern should also slide the teeth, right? Change the interface it! If not change, use rubber ring pad
This is a professional repair, they do not know the best not to split up.
You first remove the toilet above the cover, and then see if the absorbent pad is not broken, and some are not breathing pad, so flush no, hope
You can post the picture, then, may get more enthusiastic friends advice and help, find a more appropriate valve.
Pedal flush valve is damaged, the general need for new repair, online shopping the most simple way.
