Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) So have you checked your under tank boards

Please post some progress shots as I may have to help someone with a tank swop later this year & as I understand it the boards have to be wriggled out and the tank dropped out from below

Firstly Each Morgan is different & the factory seem to be experimenting with the tank mounting method. My 2011 4/4 has 3 boards that do not rest on the chassis sides.

On the left of the image is the chassis rail. The strap with the nut showing is the tank mount.
Their are 3 boards with the aft one having a rebate of 4mm depth & 3.7cm width. The aft plank is 87.3cm wide & 16.4cm depth 2cm thick(20mm) as all the boards are. Centre board is 87.3cm wide by 5.8cm depth. Fwd board is 87.3 wide & 14cm depth. The fwd board is not rebated but tucks into a metal L shaped cross member 2.5cm depth, with wood screws horizontally through the front into the wood. the crossmember bolts to the chassis each side. In my car it buts up against the pan hard rod.
The 3 planks are held together by a strap of metal plus the strap that holds the tank bolts.
. please note the extension tang in this picture is an experiment.
This configuration of the boards allows the boards to be removed (fairly) easily.
Obviously the least petrol you have in the tank the better, but not a problem mine was over 1/2 full.
I was only replacing the rear board, so I had to cut off the bolts that hold the tank as they were totally rusted. In my case only the rear ones.Then using a punch tapped the cut bolt (M8x45mm) up & out. You can just get a small hand down the side to grab the bolt. As you can just get a socket with extension on it. I have replaced these bolts with cap heads as it is easier to put a long Allan key down the side of the tank. As I did not remove the front bolts I just swung the straps out of the way. You can just get to them from above after removing the tool tray if necessary. Next much cleaning of the M6 bolt ends & nuts on the other straps, Theses are counter sunk coach bolts so may turn in the wood. No worries to cut them off if you are replacing the planks. Do not worry about the ones in the centre plank. Also remove the wood screws only 3 were still there on mine.
Now you will have the tank straps out of the way & the other strap released. The centre board will now drop out. Don't worry about the tank as it will be sitting on the fwd & aft boards.
Now as I don't have a sky hook & the car was up on axle stands (On the X frame fwd of the Diff) I got a scissor jack & using bit of 25cm by 4.5cm of 1.5 thickness on its side (you need the gap) against the fwd board, I jacked the tank up. you only need about 1.25mm. Just enough to loosen the aft board. The aft board will now slide fwd & drop out. ready for you to replace with a new one. I used Accoya & used the old board to mark up the bolt & screw holes. Then slid the new board into place. If you are going to replace the fwd board you will need to move the scissor jack & piece of wood back against the aft board. That will allow the board to slide back & down once the bolts & horizontal screws have been removed. Be careful as the tank will try & tip fwd. If there is hardly any fuel in it you can easily move it & use a couple of wedges to help hold it at the side.
Anyway once I had the aft board in & loosely bolted I removed the scissor jack & replaced the centre board which I had cleaned up & given 5 coats of Cuprinol. Will replace sometime maybe.
Bolted everything up & replaced the small wood screws on the strap. Watch point they must not be to long or they will hole the tank.
Job Done.

Only thing I would do different is make up the new boards only when I have got the old ones out as I got the rebate a bit to wide.Those of you that are eagle eyed may note there is a tell tail of something missing from the board edge. Some cars have an L shaped side protector that extends from the front to about 2cm from the rear chassis. it doesn't really do anything & think mine was removed in the factory as the screw holes are missing. Also some cars have coach bolts holding the rear board down each side in the rebate area. Again mine has no sign of these.
hope that helps.

Great info, thanks for taking the time to post

A useful write up
I like the extension tang experiment. A useful addition to stop the tank jumping and thumping over bumps I persume.

Yes Roger. My rear board is not nor was coach bolted down so did jump. That rear bolt with the tang on it, is a cap head M6 screwed into an insert, that is screwed & epoxy’d into the board, rather than a counter sunk coach bolt.(original) The fittings are marine grade stainless steel. I have placed some closed cell foam under the tangs to allow some give. Hopefully the inserts will not pull out. Just for info, apparently the Accoya wood does not need protection. Well according to the yard that supplied it.