Fixed my rear spoiler motor!

[david dolan]

A few years ago I added the 964 electrically deployed rear spoiler to my ’79 911 SC. It’s been working great until this fall when it would no longer respond to the switch being toggled in either the up or down position. I first checked that I had power going to the motor, which I did. I then disconnected the cable from the motor so that only the electrical side was connected and tried again. First, I was surprised to have some rusty water leak out of the motor boot as I slipped it off along with the cable, not a good sign! This time while trying either up or down toggle the motor was either motionless or tried to move a little bit, that plus the rusty water led me to think my motor was the problem.



The motor is encased within a plastic shell which I carefully cut apart using a Stanley knife. Inside was my motor-looking quite bad as one can see. Look at all that surface rust!



I thought surely the motor windings were damaged after seeing this, but after cleaning the surface rust away and then having a look through the holes into the insides of the motor it looked quite OK. Now, I saw what the problem really was, it was the bearing on the end of the shaft.



That bearing should be able to rotate freely on the shaft while the motor is turning the shaft and consequently the gears, but the water had rusted the bearing to the shaft. A liberal spray of WD-40 and some brute force eventually worked it free! I then soaked the bearing for several hours in a bath of WD-40 and then rotated it on the shaft until it once again looked like the rust was gone. With that complete, all that was left was to re-grease the bearing with some white grease and re-assemble the motor casing using some super glue. I was careful to not glue the moving parts to the case; however I did manage to glue 2 of my fingers together during this process! After that I added some black silicone seal around the seam just to try and get a watertight seal. I also used some of the silicone again when I put the cable boot back on when I reattached this to the car.
The motor once again is working as it should, wing goes up when I want it to and back down as well. This was a fun job as I wasn’t sure what I’d find, but luckily the problem was mechanical so I could repair it and once again have a fully functioning spoiler motor!

[Jandrews]

Great work, David! And those are some really good photos documenting your approach and how the thing works. Don't you just love it when "fixing" something simply requires taking something apart, cleaning it up, and putting it back together! Very nicely done, and thanks for the photos.


JA