how are you supposed to know which way up these big rubber washers are fitted? is the flat side sitting on the big plastic nut or against the sink drain hole
The flat side against the nut,if it is ribbed the ribs can mould against the sink to seal it,use some silicone unless instructions say differently and don't overtighten.
Rich
May 2013
Automatic Answer
We may have found other answers which could help you.