The interior rear view mirror of my ’96 SL600 had a shake that was very annoying. Here are the step-by-step instructions on how I disassembled, repaired and reassembled the mirror.
Once I got inside the mirror assembly, it appeared that either a previous owner attempted a repair or something had disintegrated. Since this is the only mirror assembly I have performed surgery on, I’m not sure what is supposed to be in there. Nevertheless, this repair made the inside rear view mirror assembly very solid.
A couple disclaimers… The mirror assembly used in this repair is from a ’96 SL600. It is not motorized, but does have ambient light sensing technology for dimming the mirror at night, as well as the IR receiver for central locking capability. But the basic steps should be the same for any R129, perhaps with slight variation.
Also, this procedure is not for the faint of heart or type A+ personalities as it does require extreme patience towards the end. As mentioned above, my mirror assembly may have parts missing that could/would make the reassembly easier. But if I do have all the components, then patience is necessary.
Finally, this procedure does not repair something that is broken. If there are broken plastic pieces inside, the mirror assembly may have to be replaced. But if things are just loose, this procedure should work well.
Tools and Materials Needed:
1. Plastic electronic tuning tool or small plastic wedge (a small flat-blade screwdriver might be used if extreme care is exercised)
2. Two pieces of 1/8-inch thick flat rubber material, each cut to 3-1/2” x 1-5/8” (nothing special except that they must be flat; no ribs – find it any well-stocked hardware store). You can substitute 1/4-inch thick, if you want – I just happened to have some 1/8-inch in the garage.
3. Double-side tape (Do *not* use double-sided foam tape; get the stuff you use at Christmas)
1. Remove the entire mirror assembly from the vehicle by pulling the base and neck firmly in a downward direction. Do *not* pull on the mirror body/housing itself! Be careful as the force of the ‘breakaway’ may disengage the connector. If need be, disconnect the electrical connector.
2. Press the edge of the mirror assembly body along the clamshell ring to begin disengaging the clamshell piece. It’s easier to start at either top corner and work along the top. The small plastic wedge works well here.
3. Unsnap the IR receiver from the bottom of the mirror assembly.
4. Remove the clamshell ring from the body. CAUTION: Be careful here as mirror components may be loose on the inside and may fall out when the clamshell is removed. In particular, watch out for a pair of brass flat springs. They are large, but may spring out – not violently, but with enough force to scoot under a table or cabinet.
5. Disconnect the 7-pin connector from the back of the mirror. This is the circuitry that controls the mirror nighttime dimming function.
6. Once apart, investigate as to the cause of mirror looseness. In my case, two springs became disengaged and allowed the mirror to flop. There may also be a situation where something broke. If something is broken, you will have to evaluate whether repairs can be made.
7. Assuming the mirror is simply loose and everything appears intact, proceed to add some thickness behind the mirror. Using double-sided tape, adhere the two 1/8-inch thick rubber pads together to form a 1/4-inch thick piece of rubber.
8. Using a small piece of double-sided tape, adhere the rubber pad to the flat section of the gimbal assembly. If the rubber is cut to the dimensions shown, it will be obvious exactly where it is to be mounted.
9. Gently bend the ends of each pressure spring together a little to increase the overall height of the spring. Do *not* over bend! You only want to increase the spring strength a little. The spring on the right is what came out of my mirror assembly, while the one on the left is one that I just bent. This should give you an idea of how much to bend each spring.
10. Adhere a small piece of double-sided tape to the indention of each spring.
11. Place both springs on the side opposite the mounted rubber pad. The indentions in the spring mate with a corresponding rib. This sets the alignment of the springs.
This picture shows both springs in place. Also note the 7-pin connector is now properly routed through its holder loop.
12. Reconnect the 7-pin connector and lay the mirror on top of the rubber pad. Do *not* adhere with double-sided tape – the mirror must be allowed to shift and settle, as the final assembly proceeds.
CAUTION: From here on, a lot of patience is required.
13. Gently sit the prepared gimbal assembly with mirror into the mirror assembly body. The springs must sit on the two ‘spines’ within the body. Patience is required because even though there is double-sided tape to hold the springs in place, they shift quite easily. You will probably have to attempt a number of times to get it properly set in place. In my case, I believe there is a piece missing that maintains a set distance between each spring. Without it, the springs can shift a little. Nevertheless, it can be accomplished, with a little patience. Please note that the mirror has been removed from this picture so that the springs can be more easily seen.
This picture shows the gimbal properly in place with the mirror resting properly on the rubber pad.
14. Carefully reassemble the clamshell, starting at the top. Use care here so that the spring alignment does not get disturbed. As you add pressure onto the clamshell, the springs will provide force which will hold the mirror firmly against the clamshell. It’s the rubber pad and added spring height that accomplishes this.
15. While holding the clamshell and body, check to make sure the entire assembly is tight and nothing is loose. If properly assembled, the mirror will be quite firmly held against the clamshell. If not, disassemble and investigate. More than likely, one on the springs is loose.
16. Snap the IR receiver into the bottom of the mirror assembly. The mirror assembly is now completely reassembled and can be handled as a single unit.
17. Using a dab of grease or a quick shot of WD40, lubricate each end of the spring at the very top of the mirror assembly. This will aid in snapping it back into place.
18. Reinstall the mirror assembly into the vehicle by connecting the electrical connector. As the mirror assembly is maneuvered into place, be sure the electrical connector is placed in its space – there is a small well for it so that it does not get pinched.
19. Using a firm upward motion on the upper mount, snap the mirror assembly in place. Do *not* exert force on the mirror body.
20. Test IR receiver function.
21. Enjoy a jiggle-free rear view mirror!
Thanks to symplered
for the suggestion of lubricating the large spring when reinstalling the entire mirror assembly back into the vehicle.