I have changed the diaphram washer, but it continues to drip. I have adjusted the screw, but it still seeps, have put in another diaphram, but it is the same. The ball valve is the plastic type fitted in the stelrad doulton type about 19 years old. any ideas!
It is most lightly be the joint that is between the thread and the start of the ball valve just after it enters that cistern,it disintergrates after a time however if ball valve 19 years old better just to buy new complete ball valve this used to be a problem as the arms now are shorter however the new valves have teloscopic arms so you can adjust ball location to suit
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