I'm trying to remove the driver seat from my 2000 XJ sport, but can't get the rear bolt out. It's rusted on top and so i Pblasted that, but looking at where the bolt protudes below the car I think I see the real problem (see photo). Did a previous owner weld or solder this on? Any tips on how to remove this?

​​many thanks in advance - I'm new to this

 

Essentially a captured thread insert that's parts of the seat support. If the head on the bolt is no longer usable in any way for removal with standard tools. Take a cutoff wheel and cut a + in the head of the bolt. You can then use a chisel to wedge into your cuts and with a few hits - break the 4 chunks off. When the seat comes free and you remove the carpet you'll have a bit of the threaded shank still remaining that you can 2nd attempt to remove the rest of the bolt or cut it flush and get creative with removing/replacing the threads/threaded insert

 

Thanks -- I'll try that. The head of the bolt is usable, but I can't get it to turn presumably because of the captured thread pictured, so I'll try what you suggest

 

That isn't going to come out. Snap it off.

Easiest way I found to fix that problem was to drill a hole in the bracket to the rear of the factory hole. Then drill a hole through the floor and put a bolt it down.