Series III Rear Floor Restoration

Hi Guys,

I have been overhauling my old Series III SWB and replacing the rear floor. I have had a section of 2mm Alu cut and bent such as the edges are bent up to rivet onto the side walls of the loadbay, into solid metal. The flanges had corroded away. I have replacement ribs and they are all Hammerited and ready to go in. I have just been placing the bits together and noticed the top of the ribs are not entirely flat. They are higher in the middle. This might be to absorb the depth of the flanges at the sides of the original floor, but does raise the question as to whether the supports ever made contact in the outer 1/4 of the floor width as the difference in height is more than a depth of Alu.

I'm also looking to find some Alu extrusion box section to replace the ribbing that was originally present in the floor (fore and aft). However, I have just noticed the heights of the recesses in the ribs are not even. The middle recess is 15mm deep. The outer two are nearer 20mm deep. I don't remember seeing this reflected in the old floor channels that were spot welded to the underside of the floor plate.

The possible explanation for all of this is that the floor is very slightly arched, but I seem to remember puddles all over the floor, so this doesn't seem to make sense. Does anyone have experience of rebuilding a floor the long way round, instead of the traditional lump of marine ply and run away.

Cheers,

Rob

photos

Hi All,

Attached find pics of the rib in question. You will note in the image showing the end (called uneven.jpg) that end of the rib sits above the table, despite the rib being placed evenly on the table. I think this may be due to it attaching to the flanges at the edge of the floor and the vertical reinforcement channels that come down the sides being folded over. So it does not touch the floor but accounts for an extra thickness at the end where it is attached.

However, you will note from the pic called arches, the outer arch is deeper than the one in the middle of the rib. This implies the central reinforcement on the original floor must have been thinner than the outer ones. I don't remember seeing this....

Cheers,

Rob

I replaced my rotten floor with a new sheet of aluminium. I replaced the ribs with ones from a 90 and dont remember them not being level. I pop riveted the sheet in place but put a rubber strip between the ribs and the floor. It seemed to work ok. I didnt repair the ribbing just took out the rot. I have carried engines in it and it seems plenty strong.

I replaced mine too with the upstands as the bottom flange was gone in parts

i thouught the cross members were flat, i only fixed them at the ends as didnt want rivets in middle of floor see pics

you can searh for top hat channel, i found a local supplier , got spare length in garage enough for swb

i glued the top hat on with high strength adhesive araldite 2015 local welders couldnt spot weld without burning holes, had half ton rubble in lots times no prblems