Hi, I'm installing a pop-up basin waste that comes with a rubber washer and a foam conical collar.
Does the foam collar sit underneath the basin with the washer or does it sit under the plug hole, but on top of the basin?
I think i understand your problem. Foam protective washer will be to stop the metal compents braking / cracking your sink. So will be an external fitting ( not direct contact with water ) The rubber washer could be for beneath the plug hole fitting to maek water tight seal. Hope this helps difficult to comment without seeing parts. If your still stuck get where you bought it from to supply instructions. Hope this helps let me know how you get on. Cheers
Regarding the washers you have with the waste assembly, the styrene one is supposed to be the water seal for inside the basin, and the rubber for the outside. To assemble, fit the styrene washer over the brass/chromed threaded part and apply either clear silicone grease or vaseline around the washer (be liberal, what it doesn't want will be pushed out and can be cleaned off with liquid soap). Now place the brass/chrome threaded part through the waste orifice in the basin and prepare the lower section of the fitting by the (liberal) application of more grease/vaseline to the rubber washer (top and bottom). Now offer the whole item up to the threaded part and tighten. this may take a few attempts to ensure the waste lever is centred at the rear of the fitting. Be patient, it is a simple matter of loosening slightly and turning the top part of the fitting either clockwise or anti until the alignment is correct. When you assemble the waste lever make sure you pack the ball part of the lever with, you guessed it, grease/vaseline to make sure you get no drips from there.
can i just add a bit of advice to this problem
before locking it all tight go and get some plumbers mate and fill the gap betweem the threaded section and the ceramics or between the washer and the underside of the basin
if you look at the waste section ie the threaded metal part it will have a seies of holes in just under the rim this for the built in overflow,but when water comes thru the plug hole area water runs down the holes and gets trapped between the waste outlet and the basin and if the washer is not tight it will leak