twhumphrey

The inside mirror on my R-class became slowly loose. Really loose in warm weather and a bit loose in cold weather. I took it apart, by prying the front surround off at the seam with a flat blade of a small screwdriver, then I disconnected the two connectors to the mirror to allow me to see the problem. I found that the ball joint has a female plastic section inside the mirror, and a metal male secton mounted ot the windshield. The plastic female tines are held tension on the male ball by a coil spring wrapped around the plastic arms. The wear on the plastic appears to cause the looseness. Thermal expansion / contraction of the spring or ball is the cause of the summer/winter difference.

To fix this I fashioned a small piece of shim metal I cut from the end of a pipe clamp and wedged it under the coil spring. I worked the coil spring off of the ball joint upwards with a screwdriver, then worked it back down with the shim inside, between the spring and the plastic of the female side of the joint. Very tight now!


The coil spring as it was installed from the factory. It was loose enough to slide easily up and down on the ball joint plastic.

The coil spring with the metal shim installed. Much tighter!