On 31 May 2007 Jim Ferguson in North Carolina, USA, wrote:
".... had a persistent problem of the rear view mirror vibrating while driving. .... It as fine at some speeds but was almost unusable particularly at driving speed (a resonant point). Tightening or loosening the screws seemed not to help in a consistent manner. I tried replacing the fiber packing with rubber, foam, etc. That home helped somewhat but didn't solve the problem at all speeds, either too loose or too tight.

"My solution turned out to be a two coil spring washers under the mirror on top of a rubber packing pad. The spring (image attached) was part of one of Todd Clarke's F-83 kit. The mounting screws were snugged but not really tight. It worked like a charm, NO vibration and a steady rear view at all speeds."


Nice work, Jim, for attacking a 50 year old problem. Thread lock adhesive may be used to prevent loosening of the "snugged but not tight" screws in long term usage.

There is hidden science here. The spring washers in combination with the slightly loose screws allow the mirror base to be "decoupled" from the body cowling. The mirror itself still has the original resonance frequency from the base up. Combination of the new soft mount with original mirror mass creates another lower resonance frequency. If the higher frequency is an even multiple of the lower frequency, it will still vibrate at the higher frequency. When the two frequencies are not closely matched (by multiple) they damp each other out and it will not vibrate. Success of the setup depends on mismatched harmonics. Fortunately it is easier to create a mismatch than an exact multiple match.

Now if I can just find an easy source for that double helical spring washer, ....

On 31 May 2007 Dominic Clancy in Switzerland wrote:
"On my car the vibration is not a problem for visibility, but the poor manufacturing of the mirror base is. The stem passes through the mounting plate, and then is distorted to hold it in place. The trouble is that vibration over the years has caused the fitting to become loose. My mirror constantly shifts in an arc from one side to another, so I am constantly adjusting it. I need to take it off and give it some attention with a BFH to tighten it up again."

On 31 May 2007 D C GRAHAME in South Yorkshire, UK, wrote:
"I had a similar problem, although maybe not so severe, and solved it by running a few drops of instant glue round the joint between stem and base."

I had the same problem with multiple copies of replacement mirrors in the late 1980's. Some of them were so loose as to vibrate dramatically. At one time I was using a rubber band around the mirror stem and two nearby LTD studs to stabilize the mirror. After enough frustration, it was apparent that buying another one would not solve the problem of poor manufacture. I finally drilled and tapped the bottom of the stem to installed a flat washer and machine screw, and banished that problem entirely. - Barney Gaylord