A couple of wash basin issues - removing a back nut from a tap and a slight leak from the waste

[mvdct]

Hi DIY not,

After recently, successfully, contending with a couple of other bathroom issues (link 1; link 2 - thanks for your help with those) - we move onto the wash basin - which has two problems.

Problem 1. The basin has an old single mixer tap. It has been leaking. And is loose. It doesn't look like the cartridges can be replaced - so I'm going to replace the whole tap.

However, I can not get the nut on the back off. This is the space I have to play with:

I have an adjustable basin wrench, but I can't get it into the space and turn it. There isn't room.

So do I need to get a backnut spanner? The nut seems to be about 40mm across at the base (wider at the top). So I'm hoping, something like this would fit and remove it (link). Would you agree? Should I be trying to measure things more precisely before buying? Thanks.

That is problem 1. Problem 2 - revealed itself when exploring problem 1. We removed the basin pedestal (which didn't have any of the weight of the actual sink sitting on it):

There is a slight leak where the waste comes out of the bottom of the basin.

As you can see the silicon looks pretty old and a bit worn. So I figure I need to replace that as well. My only concern is that the bottom of the sink doesn't look very flat and level (see above and also the image below). But I'm hoping that by using plumbers mait and a basin washer before putting the nut back on will sort that out. But I did just want to check your thoughts - in case it looks like the whole basin needs replacing or something else.

In short:

Problem 1: Do I need a backnut spanner? Would this one work?

Problem 2: Should I be worried about the apparent uneven levels at base of the basin, or should plumbers mait and a washer sort that out?

And finally - question 3: what order would you do these jobs in? Waste then Tap? Or Tap then Waste. Or doesn't it matter?

Thanks all.

 

[oldbuffer]

1. That looks like a Vado "Elements" basin mixer. If so, the cartridges can be replaced. The round chrome plated shrouds below the handles unscrew (normal right hand thread) and the handles come with them, revealing the tap works which can be removed and replaced in the usual way.
2. If you do decide to replace the taps, the spanner you refer to should do the job. You would need to detach the flexi hoses and feed them through the spanner first, or cut them. Alternatively you could use a spanner to hold the nut, remove the tap spout and rotate the body of the tap to undo.
3. With respect to the waste and its leak:
3.1 Remove the trap (white plastic).
3.2 Undo the black plastic back nut and remove the waste.
3.3 Clean all old silicone and PTFE tape of the waste threads.
3.4 Refit the waste with:
3.4.a Plumber's Mait rolled into a thin "sausage" between the waste flange and the upper surface of the basin.
3.4.b A "basin mate" washer between the underside of the basin and the backnut.
3.4.c Replace the black plastic back nut with a brass one (1 1/4" BSP)
3.5 Clean and replace the trap.
4. Order of jobs not relevant, but easiest to:
4.1 Remove waste and trap.
4.2 Remove tap and replace / refit.
4.3 Refit waste and trap.
5. Put a bucket under the waste hole so that when you turn the water on by mistake it doesn't cause a flood!

 

[mvdct]

Much appreciated @oldbuffer. Thank you.