96 Park Avenue vibrating mirror

I saw there was a service bulletin for this problem but could not access the bulletin. What can I do to tighten this mirror up.It does not have a screw just a clip.I tried bending the clip but no help.Can I wedge something in there to tighten it up? This is the one on the windshield.

IIRC, a replacement bracket and clip can be had in the Dorman/Motormite "HELP!" section in some auto parts stores.