Plastic toilet float valves - drip from threaded nut!!

[jacobball]

Hi

Just a quickie - why do plastic float valves (in toilet cistern's) always seem to drip where the arm part connects to the valve body, the part you unscrew when chaging the diaphragm or cleaning the valve seating?

I noticed mine was dripping this morning, even before I unscrewed it to clean it out. It still does it now after I have re-done it up. I haven't cross-threaded the joint either. Will this cause an overflow after several hours?? Or is this kind of normal with these plastic float valves?

 

[kirkgas]

a leak is not normal, and yes it will cause an overflow, probably overnight as the loo isnt used, you will need to seal it, it might be a poor thread so use some ptfe tape (i know it shouldn't be req'd before you all shout) but the OP says it is leaking and has been removed and refitted