noisy toilet cistern

[AndyPRK]

Toilet cistern connected to mains supply.

When the level was getting high, and the valve shutting off it made a noise.

I took the seal out and refitted, the flow was reduced and it didn't make a noise, but the seal no longer completely sealed.

I fitted a new seal. Water flow back to normal, but the noise is back and its even worse 2 weeks later and its the same

Any idea's ?

 

[buck51]

rewasher or replace the ballcock

The quality of washers varies try a different one