Single lever kitchen tap problem

A spot of thread lock? (Assuming it is a screwed in fitting of some sort.)

I don't know if this might help....

I found the metal of the U shaped plate was too thin - hence it would bend a little each time it was tightened. Soon after being tightened the tap would be loose again. Replacing the U plate with one I made myself from thicker steel completely solved the problem.

Screwdriver might be the clue. These taps have a brass rod that screws into the tap body, tightened by using a screwdriver in a slot in the end of the rod. The holding down is done by a crescent shaped metal plate that slips over the rod & tightened by a nut. Is that the type?

It seems that the brass rod isnt threaded into the tap body properly. Undo the nut a bit & use mole grips to really tighten the rod into the tap, then do up the nut tight.

Using a Mole wrench is a good way to mangle the threads on the brass rod!

If you use a decent screwdriver on the end of the rod while the nut is slack, you can get it tight enough. You then need to tighten the nut itself using a box spanner or socket spanner. If it's like my monobloc tap, you need to be good at working by feel - 'cos there's no way I can get my hands on the relevant bits and get my head in the right place to see what I'm doing, at the same time!

But it won't matter - until the time comes to remove it completely, then you just use mole grips again.

The bolt is loose and needs to be tighted up very well into the tap body - a large screwderiver can do that. The nuts require tightening along the bolt with the likes of these:

Ecxept that you probably need to remove the nut in order to expose enough of the threaded rod for the Mole wrench to grip on!

Do NOT use a mole wrench.

I'm following this up on the basis of advice given - for which, thanks to all - and we'll see how it goes. :-)

No. You have, from the top;

Tap body, sink, rubber cresent washer, metal cresent washer, nut, protruding rod. Slacken nut & you still have an inch or so of rod to grip.

Would a hacksaw be better?

Most clearly.

The message from "The Medway Handyman" contains these words:

One *could* use a couple of nuts nearer the outer end of the threaded rod, but Dave has made the vital point that the simple, logical way is to use a Mole wrench on that part of the threaded rod which does not actually need to be threaded at all. It's cheap and easy for the manufacturer to use a simple piece of studding and cut a slot in one end of it for a screwdriver, but in point of fact that part of the length of the rod to which Dave refers can have the tread deformed without any damage to the thread on the parts of the rod where a thread is needed. If, as is common, it's a bit of soft brass studding, it's all to easy to damage the slot in the outer end and difficult to get it really tight without damaging the said slot. Murch better to deform a bit of the rod where the damage won't matter.