Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Vibration on Passenger Side

Check the body frame to chassis mounts - closest to that area is the point by passenger right knee. Depending on year of build, there is either one or two screws/bolts that attach the wooden frame to the chassis.
They normally come loose and sometimes they are not there at all....

Stevo666 - looking at the diagram of the chassis in the M3W Parts Book, there seems to be some sort of bracket with two fasteners that connects to the frame on the forward side of the chassis cross member (under the dashboard). I hope that makes sense. That would make the bracket and fasteners somewhere around the thigh of the passenger. See circled area in top right of photo below. Is that where you are talking about?

I do not see any other brackets or fasteners as you go back along the chassis under the arm rest and along to the back of the seats. That's where the fastener shown to the very right in my photo attaches the wood frame to the body panels. It that fastener supposed to keep the wood frame slightly above the metal chassis there to avoid vibration? It certainly sounds plausible given the noise location and tone.

I've checked the chassis to frame connection by the dashboard cross member and all seems in order. However, there does seem to be something odd going on by the arm rest. Even though the red side paneling by the armrest is fastened at each end, I can still pull the plastic / fiberglass (whatever it is) away from the wood side frame. This is where it meets the top of the metal chassis. See pictures 1 and 2. In picture 3, I can easily slide my fingers behind the panel and between it and the wood frame behind it. Picture 4 shows it close up. The red side panel is pulled out, the black tube chassis is below, and in between, I can see some sort of black tape. In the photo it seems to have a red band along it. This "tape" seems to be along and on the face of the wood frame. I'm guessing it is there to bond the panel to the wood frame immediately above the chassis. Can anyone confirm?

I don't remember it being this loose before. The car is with me, here in South Florida, where we have real issues with automotive glues coming unstuck. My Audi's rear window of its convertible top is a good example. Within months of moving to S. FL the glass delaminated from the fabric where Audi had glued them together. It looks to me as though a similar thing is happening here with the M3W. I cannot find anything in the M3W Parts Book or online about how the frame, chassis, and panel all come together in this area, but it looks as though there is some sort of tape, Velcro, or glue that bonds the panel to the wood frame along the length of the area below the arm rest (and between the fasteners at each end). When I push my finger underneath the panel and away from the wood frame and then let go, the panel snaps back into place and makes the same noise (not as loud) as when I'm driving. I think at certain frequencies the vibration makes the panel strike the wood frame and it acts like a drum with loud reverberations going through the car. That would explain why, if I reach over and squeeze the panel below the arm rest at the back end, the noise immediately stops.

Assuming this is the root cause - and I await speculation / confirmation from the M3W Experts - I need to secure the panels to the side frames on both sides of the car. More glue or epoxy, particularly those that are heat and moisture resistant would be an improvement on the original, but using the same approach. I think it would be only a matter of time before that too failed. What do you think of the idea of adding two or three more mechanical fasteners like the one on the very far right of the first (top) photos? The existing fasteners screw directly through the side panel on the inside of the vehicle and into the side of the wooden frame. Spaced 6-9 inches apart, they would be enough to hold it together and stop the flexing and vibration. I could also put some fabric tape, like the stuff I think it actually there now in the last photo, and screw through that as well, securing a material buffer to reduce vibration even more.

Thoughts please?

For anyone that is interested --- today I Pushed some packing material up inside where my finger is in the last photo. Took it for a spin - and no vibration! As best I can work out, MMC used some sort of tape / velcro product between the panel and the wood frame under the arm rest. In a relatively short period of time here in Florida, the heat and humidity weakened the bond and the velcro came unglued from the panel. When driving at certain speeds, the newly freed panel vibrates against the wood in an area where there is no tape or fastener - again, roundabout where my fingers are in the photos. This vibration causes a very loud and unpleasant noise. My proposed fix is to put a strip of neoprene along the face of the wood frame under the panel and then fasten through the panel and neoprene into the frame. There are already two screws, a long way apart, at each end (one by the backrest, the other closer to the dashboard). I'll try to find similar fasteners and add a couple underneath the armrest to more securely fasten the panels on both sides of the car. I don't want to glue anything down because as soon as I do something like that, I'll need to remove the part for access!! Thanks for everyone 's assistance and suggestions!

I had the same issue on the passenger side of my 2013 M3W a loud vibration rattle at certain speeds. I simply put a strip of 1/2 inch foam pipe insulation behind the panel and have never heard the rattle again.

Stevo666 - looking at the diagram of the chassis in the M3W Parts Book, there seems to be some sort of bracket with two fasteners that connects to the frame on the forward side of the chassis cross member (under the dashboard). I hope that makes sense. That would make the bracket and fasteners somewhere around the thigh of the passenger. See circled area in top right of photo below. Is that where you are talking about?
Yes - thats the brackets I was talking about. Earlier cars are missing the upright part of that bracket.
Regarding side panel foam - quite a few m3w's have long strips of foam added to this side panel along the inside - stuck to the panel and big enough to also slide down behind the chassis tube.

Stevo and Bruce - you're talking about the space above the metal chassis and between the armrest panel and the wood frame, right? In other words, where I have my fingers above?

I solved the problem today by adding another fastener or two along the top of the metal chassis, screwing the side panel into the wood frame. I used the same stainless steel fasteners that are at each end, so it looks original. The panel is now uniform looking. I didn't want to add foam behind the panel as it seemed be be causing an irregular bulging in places, i.e. it wasn't even.

Took it out for a spin up along the ocean this evening. Weather was perfect. Now I can hear that low exhaust note cleanly and clearly again, without having to worry about that loud vibration noise. There's still the usual "box of spanners" sound from behind the dash, but I'm working on that too!