Same thing here. Caught loose bolt at the last second. Almost lost it. Gromet gone. Gromet apparently does very little. Ordered new bolts and will carry an extra. Remove crank arm. Clean taper area of the crank and arm thoroughly with acetone. Same to bolt threads and threaded inside end of crank (q tips). Apply liberal amount of blue locktite. Tighten to correct torque spec. Let it sit overnight. Ride on! :-)