Replacing 110 rear floor

Hello! Newby to this forum here. I've searched previous topics but not found any answers to my problem ..... can any body help please?
The (loadspace) floor of my 110 300TDi landy is corroded to bu**ery. I have access to free alloy sheet and most types of welding equipment so I am wondering "how big a job is replacing the floor?"
On the suface it would apppear straight forward and would give access to the chassis for better crossmember replacement

Not too hard. I think you have some spot welds to drill out.

Biggest problem with 110 rear crossmember replacement is the fuel tank in the back and the loom inside the chassis on the off side.

Great news. Thanks for the response. Yes, I noticed the tank and have been running the contents down to empty. I noticed that some suppliers of crossmembers show the floor support brackets as being provided but most just have the cr**py little angle iron spacer. If I can get the floor off I will be able to patch up the brackets from above.
Thanks again.

If the 110 is the same construction as a 90 then you need to drill out the rivets along all four sides of the floor pan. There are some spot welds along the front and back edges that will also need drilling out or breaking with a cold chisel if you are not bothered about keeping the old floor. Clean and paint everything once the floor is out. Cut the new sheet to size and rivet the floor strengthening supports from the old floor to the new one. Run a bead of sealant (I used clear silicone because I had some) around the edges and re-rivet the floor back in place. Sorted. I did mine in a day. Hardest bit was drilling the spot welds.

As you say it also makes access to the chassis and rear suspension nice and easy. I changed all my rear suspension bushes and the A frame ball joint while I had the floor out and gave the chassis and rear x member a good clean and coat of hammerite.

Excellent! Just what I wanted to hear. For some reason I was expecting the response to be "for heaven's don't do that ... you'll distort this or you'll never get that back " etc

Good idea about the bushes etc

Many thanks