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MG MGB Technical - Fixing fule/gas tank

We have removed the fuel/gas tank but there are problems with fixing. Notably on the RHS there appears to be a flange on the chassis/body through which the tank bolts go BUT on our car this is bent and damaged. Does anyone have images to show how this flange should be?

Thank you

Bob Marshall
R J Marshall

Is this any help?

Dave O'Neill 2

What age is the car? The fuel tank design changed. The early cars had a tank held by two straps. From March 1965 the tank was redesigned and bolted directly to the floor by its flange. This persisted to the end of production. I'm not sure I understand which part you think is damaged.
Mike Howlett

Dave

Yes this does help but it is not clear (to me) how the fixing bolts fit. On your csr is there a flange on the chassis which holds them or are they captive? On my car there is what appears to be a twisted flange (which obviously someone has had a go at. The fixing kit from Moss consists of captive nuts which either slide onto this flange or onto the tank. If they fit on the tank how does one tighten the bolts? The bolts are not accessible from inside the boot or should they be?

Mike
It is a 68 GT which has 8 bolts holding the tank to the boot floor. Hopefully the above will explain my problem.

On the LHS the bolts go through the floor except one which is captive and as is usually the case it has torn away - more welding!

Bob
R J Marshall

Bob

There are nine fixings in total.

There are five captive nuts which attach to the flange on the tank. There are also four studs which are fixed to the boot floor.

I can take some more photos later, if that would help?
Dave O'Neill 2

The right-hand side on my 73 has a floor stud adjacent to the chassis rail by the rear corner, another by the front corner, then a bolt through the boot floor to a captive nut on the tank flange between them.

There are no flanges (as I understand the term) in the boot floor that you could slide a captive nut onto, it should be solid, albeit with pressed strengthening ribs.
Paul Hunt

Here's another photo which might be a bit clearer.

The studs are marked with white arrows.

The blue arrows are pointing to the holes in the bootfloor. This is where you use the captive nuts, fitted to the corresponding holes on the tank flange.

Dave O'Neill 2

Gentlemen

Thank you all for your help.

What has caused my confusion is that someone had on the RHS split open the box member which carries 3/4 captive bolts (or were they originally nuts?) which made it look like a flange. The solution is to trim the jagged edges and fit new captive nuts which slide over the edge. These are available from Moss. The fuel tank had been replaced at some time and a new boot (trunk) floor fitted but they left behind rotting elements of the old floor. These we have ground down, Kurusted and heavily painted with red oxide so it should last. We thought of repairing the boot floor or relacing it but our tame planisher advised against it.
All this came about because at Le Mans the car was obviously low on the springs and removal of the old springs revealed no bump stop and in order to weld a new one on everything had to be removed.
The moral? Take up knitting!
R J Marshall

This thread was discussed between 26/11/2014 and 28/11/2014

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