Toilet makes screeching sound when flushed

[trainee]

Hi

The toilet next to the stop valve has started to make a screeching sound when i flush the toilet. i've tried lowering / increasing the water pressure but it doesn't make any difference. the sound is worse when i turn the tap on to wash my hands - it sounds like a fog horn then! It's really embarrassing when people use the toilet and i've asked the local plumber and he doesn't know what the problem is.

Any suggestions?

[neilalexander61]

Same problem is affecting my upstairs toilet. Is it air in the system perhaps? Does anyone have any ideas?

[plumbbob]

The rubber valve has perished and become hard causing it to oscillate when water flows past it. Either replace the rubber or preferably the entire valve.

Turning the water down at the main stopcock may reduce the noise.