Rattles

The causes of rattling at an M55 can be very diverse, but can be remedied with the appropriate know-how:
For example, the pedal unit is not designed to be particularly stiff. This is evident from the fact that the lower crossbar moves when the pedal is depressed. An additional aluminum profile parallel to the bar remedies this. The pedal's rotating unit has no defined preload. Either it is stiff (nut tightened), or it is too loose and can produce noise. On my very old M55, there are no plain bearings for the pedal joint itself. Again, the bolt preload had to be selected so that the pedal moved freely but did not rattle. The remedy is plain bearings with an axial attachment. The attachment of the pedal rod to the pedal is often stressed by bending during transport and therefore tends to deflect. In addition, the clamping device of the pedal rod on the damper beam can generate noise in an unfavorable rotational position. In both cases, a remedy can be found by using a strap instead of the rod.
The rivets securing the resonator tubes can loosen with frequent transport and then cause noise. On one instrument, I drilled out the rivets and replaced them with screws (from the inside) with nuts on the outside. At the same time, I put a rubber washer between the resonance tube and the brackets. Another common reason for noise is that the damping arm bearings are worn. These can be replaced if necessary, as can the mount for these plain bearings, which are simple bending plates that are not particularly well defined. Of course, over time, various parts of the frame may have loosened. This must be listened to and eliminated step by step.

The underframe of the M55 is kept relatively slim and thus capable of swinging. Accordingly, you must make certain checks (especially in the pedal area) regularly.

Eliminating rattles is a challenge especially since a vibe is also meant to create and carry sound. JM Piper had a great suggestion to buy a cheap stethoscope and put a rod into it so you can sneak it down between things and find sounds. I use a 2 foot hunk of hose. I've had worn noisy wheels, the newer adjustable height frames rattle inside the legs. You can wiggle the damper pedal up and down. Worn cracked wood parts will rattle, so will loose screws. It does require some detective work for sure. By nature of the Omega vibes their damper and pedals from what I've heard are much quieter. I've only heard new Omegas, so I can't comment on quietness of the tremolo mechanism. I agree with Prof W. it is possible to get rid of the rattles. If your M-55 is older, adding "M" braces can help a lot. an almost universal rattle reducer is to wrap some teflon tape around the hook of the damper rod (and/or the eye bolt). It's the part that attaches the felt damper to the pedal. I have replaced the rivets on resonators, per above. however, I've also gotten a really big socket and a bunch of extensions to reach up in the resonator tube and hit the other side, firmly to tighten up the rivet. But you do run the risk of denting something.

I saw Gary Burton's last concert in Indianapolis, it was on an M-55 with a lot of duct tape added.