Here is a repair DIY for the inside mirror of the W210, the one with autodimming and IR remote built in (also applies in part to the W140 and perhaps other models). The problem is that plastic tabs holding springs on the inside of the mirror assembly break like the cheap plastic toy it is, leaving the mirror floppy. As replacements are expensive, many have worked on techniques for repair. My method was shamelessly stolen from forum member Bourman, who wrote post #24 in this thread. Thank you, Mr. Bourman. My contribution is mostly the addition of the pictures.

Warning: DO NOT turn on the ignition after disconnecting the mirror. To do so may confuse the electronics, requiring (at least) re-synchronizing the IR transmitter and receiver when you're finished. I would be happy to be proven wrong; please don't prove me right!





Many writers have covered removal of the mirror from the car. With a hand on each side of the mirror, pull down on the right side firmly and the spring connection will pop loose. Don't pull too far, there's a cable inside you don't want to break. Separate the cable plug/socket and take the mirror assembly to a safe place to work on it. The next photo shows the spring-loaded tabs that keep the mirror attached to the roof. Several other MB models use the same mechanism—W124 and so forth.





Disassembly begins by prying off the lower piece that holds the IR sensor and red/green blinky lights. Notice the four tabs that hold the piece onto the mirror. It's easier to let the IR sensor piece dangle on its cable—the connectors (if they exist) are somewhat hidden, at least I didn't spend time looking for them.





Carefully pry the two halves of the plastic housing apart. It is possible that plastic bits and flat metal springs may fall out as you do this so best to operate on a clean towel in a cooky sheet.





Separate the two halves. Keep the half with the mirror in it and put the front half away until time to reassemble. The inset picture shows the two broken bits of plastic that made my mirror flop. One fell out during disassembly while the other one was almost ready to fall out and was doing little good.





This next picture shows one of the broken plastic bits held in its proper place with a hemostat; the inset shows the front mirror half without that bit. The two springs that hold the mirror and the mounting arm are supposed to be hooked under those broken bits; without them there's little holding force, which is why the mirror flops.





Since it's difficult or impossible to glue the plastic bits back onto the mirror shell, forum member Bourman came up with the idea of drilling a hole through the casing and the end of the spring and using a screw to hold the spring in place. This picture shows an end of the spring (both ends are identical) before and after drilling. Use a 3/32" or 7/64" bit and make sure it's a good one—the spring is made of fairly hard steel as my slightly off-center hole shows.





The hardware I used consisted of a 2.5 mm screw with matching nut, a couple of washers, and a little piece of brass tubing as a spacer. Obviously you can use SAE hardware too—but 4-40 is too large, you'll need 2-56 or 3-48. Remember to put together two sets, one for each spring on the left and right sides of the mirror.





I drilled the matching holes in the case with a Dremel.





Now put the screw through the case, add the spacer, bend down the spring, push the screw through and tighten the nut. Do that on each side and the mirror is repaired—it will no longer flop.




To finish, reassemble the mirror making sure not to pinch any wires. Take the mirror out to the car, reconnect the plug/socket, and push the mirror bracket up into place in the roof. Insert the left side first, then push up hard on the right side. Push on the base, not on the mirror. It takes considerable effort but eventually it pops into place and you're finished.

Reminder: So long as you haven't turned on the ignition with the mirror disconnected, you should not have to re-synchronize your IR transmitter and receiver.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Great post!. I threw the towel long time ago trying to fix it. Texas sun plays havoc on plastic(s).

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06 MB E320 CDI 123k miles
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11 GL350 Bluetec 136k (Sold)
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