UK bathroom basin drain backnut.

[Keith1002]

I am currently trying to change my bathroom sink drain (uk). I have very little room to get in behind the basin leg to remove the drains back nut. I have tried to remove the back nut with knipex water pump pliers, but the plier handles hit the wall so I can't get the back nut undone. I then tried a stubby wide jaw adjustable spanner, but again had no room to turn the spanner to undo the nut. I bought a basin backnut box spanner which can remove 46mm and 50mm nuts. After trying this, it seems the 50mm end is too small for the backnut. Has anyone any idea what size the backnut could be? It says online that most basin backnuts are 1 1/4, so I've no idea why this one is bigger than 50mm. Or if you have any other ideas on how to remove the drain? Thank you. Any advice is much appreciated.

 

[CBW]

Ok, I think you’re on about the slotted waste, as opposed to the drain or trap. The size is 1.25” because it’s the size of the thread, not the backnut size. If there’s a pedestal in the way, can I be removed slightly or fully but supporting the basin? Then use footprint wrench, or water pump pliers and usually 2 screwdrivers down the slots to steady the basin waste.