BMW Z3 Mirror Base Refurbishment
Article submitted by ‘r37′ (Dan)

This guide is mainly for those of us whose mirrors are so badly corroded they cant be twisted to access the bolts. Theres no extra work per se but the removal process is somewhat backwards.

1: Remove your doorcard by prising out the mirror adjustment switch with a flat bladed screw driver, sliding the black trim around the door handly forwards (watch out for fingernails here) and then undoing the hex bolt hidden away where your mirror switch used to be. Using either your fingers or a trim removal tool prise away the 6 clips that hold the door car on, lift the back of the card and the whole thing should pop off nicely.

2: Undo the speaker wire and the wire shown in the picture, this will allow the mirror connection to be pulled through the door.

3: Temporarily plug in the mirror adjustment switch and adjust the mirror so the edge closes to the car is as far back into the housing as possible. Gently slide a flat bladed screwdriver into the open side and insert it between the black mirror plate, and the white motor plate and twist. This should pop the 4 clips that hold the mirror on without putting any stress on the glass, hopefully avoiding any breakages. Once one side is done just follow it round with the screwdriver.

4: Undo the 4 hex bits (T10) and then pull apart the mirror casing, this should leave the aluminium unit behind and give access to the bolts.

5: The first bolt is easily accesed with the screwdriver attatchment on your stud bit, the bolt under the mirror unit is more tricky. Place the bit into the bolt and use some pliers to undo it, its fairly easy as the bolts arnt overly tight.

6: you can then pull the entire unit off the car. Be careful with the plastic clip you undid earlier, dont just pull on it if it gets stuck. If it breaks you’ll need a new mirror.

7: Depending on your level of corrosion you’ll need to sand back the respective areas, as you can see mine was terrible so i took the base back to bare metal all round. Any sanding marks here will show in the final finish so go up to atleast 400 grit on the areas you have sanded.

8: Mask up and prime the bases using acid etch primer, normal primer will struggle to stick to the bare aluminium and may flake off. I used UPOL #8 Acid etch primer and this is dry enough to paint in an hour and doesnt need flatting. If your base has deep pitting then apply a layer of hi-build primer, wait 24h wet sand with 1500 grit paper.

9: apply your colour coat and then your lacquer. I used a pre-mix rattlecan from halfords that can be lacquered in an hour and followed with a can of clearcoat i had floating round. Painted and waiting for clearcoat.

10: To refit the mirrors feed the cable through the hole in the door, fit the 2 bolts that hold the mirror together, re-fit the mirror case and screw back together using the 4 hex screws, plug in the mirror switch and make sure the motors work, unplug it and refit the doorcard, then push the glass back on. Bases back on the car and needing a polish up.


When sanding i started at 60 grit, moved to 120, then 250, then 380.

I used a file on the top part because the corrosion was very extensive just be sure not to alter the shape of the base too much.

Make sure you use some sort of mask! The etch primer was truly horrible stuff, i did a quick touchup without a mask on and it burned the insides of my nose and gave me a whacking headache.

Leave the clearcoat for a week to fully harden before you polish it.

While your doorcards are off clean out the crap that has settled in the bottom of your door and give it a protective coat of waxoyl, grease your runners aswell.

I’m not 100% happy with the final finish. The lacquer I used was fairly old and tended to spit out paint rather than a fine mist so its a bit rough, will need to be polished up after it has cured properly.

My rubber gasket allready had primer on it, pointing to a badly done re-spray in the past. If yours is very dirty/brittle then the part numbers are 51167001039 for the left one and 51167001040 for the right. RealOEM doesnt list the prices but I would have thought they would be cheap.