I'm trying to change a bath tap (faucet for our American friends). On the hot tap side, the nut which holds the tap onto the bath is seriously corroded, and I can't unscrew it.
As always with bath taps, everything is made more difficult by having to work in a tiny cramped space between the bath and the wall. I'm doing it all lying on my side on the floor with my arms fully extended, it's really awkward.
Here's a photo of the offending nut: I can wiggle the tap around and can see that it's not stuck to the bath itself, it's just stuck to the screw thread.
I've had a go with water pump pliers, and two different kinds of basin wrench:
With the first one of these, I managed to get a really good grip on it, but even pulling the two rods I wasn't able to shift it. I even managed to repeatedly bash one of the rods with a hammer but still no luck.
I'm stuck now because the water is turned off for the house (because of course the isolating valves below the taps are corroded and jammed too so I can't turn them off properly).
Any ideas, anyone? Should I just keep bashing the basin wrench with a hammer? thanks
EDIT - it's hard to see where the nut ends in that picture, but it includes the flat part above - it's one of these basically: