Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Pop rivet failures below rear exhaust mount

I noticed an increasingly horrible noise coming from the mid regions of my M3W. On examination, I found multiple pop rivet failures on the lower side body below the rear exhaust mount, both in front and behind. My first question is does anyone know what size they are. On a quick look, they seem to be either large head 1/8" or standard 5/32" = 4mm. Would I be better drilling these to 4.8mm or 3/16"? I do have both sizes of rivets. My other thought would be to put a strip of double sided industrial adhesive tape between the outer body and the inner panel, as a vibration damper. I run G56 exhausts and obviously with the double flexy sections, there is quite a lot of vibration transmitted to this area of bodywork.

Wilson

I think the rivets you are referring to fix the body to the chassis.

Check out this THREAD

Your cars chassis has just been replaced, I think? These rivets should have been replaced at the same time as they are part of the fixing of the body to chassis. When the cars are made there are usually a few unpainted rivets that were fitted after body paint in this area.

I also run the G56 exhausts and find that the double flex sections seem to reduce the amount of vibration transmitted to the silencers over standard, although it is hardly vibration free and they are heavier.

I will order some 5mm x 16mm SS rivets. I have one of the large double lever riveters, with 2 foot long handles which copes with up to 10mm diameter rivets, so 5mm SS will be no problem. I suspect these rivets were replaced with too short and soft rivets at the time of the chassis change. I will also order some fibre washers to go between the body and the chassis but I did wonder if a long strip of the double sided adhesive industrial bonding tape might be a better idea than the fibre washers.

Thanks for information guys.

The fibre washers will leave gaps whereas a single strip of tape will give a continuous seal. Small gaps at seams and joints are terrible for water penetration and retention and subsequent corrosion. A good mastic type sealant pumped in might be a third option to consider.

I have bought a lifetime supply (box of 100) of 5mm x 20mm stainless steel pop rivets. I bought 5mm as they have larger heads than the 4.8mm for some weird reason. Also I have a 5mm drill but not a 4.8mm or any imperial drills with me in France. It was not a lot more to buy a box of 100 rivets (€17) than it was to buy 25 (€10) from the German engineers' suppliers. The quickest I could get a French supplier to send them was three weeks. So if anyone needs a couple of these rivets, I am happy to pass them on at postage cost to me and pop (ha ha) them in an envelope.

Wilson

Yes, had at least one rivet failed when I picked up my M3W after chassis change last October. A few odd clonks occasionally and may be a few rivets not doing what they're supposed to! Must check again, despite a lovely drive out yesterday afternoon!!