went out to this one today, didn't really have time to look at it properly, the original complaint was when the cistern was filling, instead of the water shooting down from the valve, it was spraying up and seeping out behind the lid,
I went to have a look and this was the case, only when the water reached the level of the 'cup' on the torbeck valve, it didn't stop the water, and the cistern would overflow down the pan. I tried lifting the arm of the valve up manually as the cistern was filling to see if that stopped the water but nothing did, I think someone may have messed with it before I came.
I didn't even bother to take the valve apart as I was in a rush, I will go back Monday with a fluidmaster I think, or do you think a new diaphragm would solve the problem?