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Fixing the rear window wiper motor

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This approach has worked for me so far, on my 1986. Like any instructions here in Renntech, use at your own risk. But if the motor is still working, likely all you need to do is clean the accumulated crud from the gear system.

1. Remove the plastic cover that is over (under) the motor assembly. Pus on the top slot and it will disconnect. Turn it upside down as it is a handy place to keep all the nuts and screws you will remove.


2. Test if you are getting power to the motor, ignition on, switch on. If you are getting power, proceed with rest of steps. Turn switch and ignition off. Remove the connectors and remember how they go. Here is a picture just in case.


3. Remove wiper, using 10 mm socket on wiper nut and lit wiper arm out. Then remove rubber grommet with small flat screwdriver, then the 17mm nut right below the rubber grommet


4. Remove 3 10mm nuts from motor assembly, the ones that hold the assembly to the black plate


5. Now you can gently remove the assembly from the hatchback, gently pull away fromt the glass it will come off. The black plate will come off too, as it is held to the the hatch with to "fingers" only towards the back.

6. Remove the motor assembly from the black plate, simply pull appart


8. Remove the flat head screws that hold the bottom plate to the motor gear assembly. And look at the accumulated gunk that prevents the motor from turning.


9. Now, with your wife's permission, take the whole thing to a table and begin cleaning out the solidified gunk. I used Gumout, and ended up going out to the driveway and spraying liberally over the gears.


10. Remove the C clip from the top side gear shaft for the main big gear. Push down the wiper driving bolt and then you can remove the big gear. Clean the gunk out.


11. Oil the gears and replace them back into their position. Secure big gear with C clip. Replace bottom plate with the flad head screws.

12. Connect the power connectors back to the motor and have some turn the ignition and rear wiper motor to test if it fixed the problem. If it did, you are done and reassemble the components. If not....

13. The motor may be binding or too dirty. Dissamble the motor and housing. I used Lectra Clean electrical part cleaner to remove the rust and dirt from the magnets


14. Another steps is related to the motor shaft binding on the bearing on the rearmost section of the motor assembly. I removed the bearing and working to relace it with a different softer material (nylon). Will post those pictures as an update later. But for now, the motor and wiper work, they are just noisy.

Edited by Izzy
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  • 5 months later...

Thanks for the great info! I recently had the same issue on my 1995 968 and used your info to get it fixed. However, I ran into what might be a one-off cause.

After removing the electric motor from the gear case and applying power, the motor worked fine and was clean.

The gear case was riveted together instead of screwed. Maybe they did this on later model years. After removing the rivet heads and opening it up, I found that the center shaft the main gear rides on was not pressed all the way down into the case, colliding with the drive arm and preventing it from turning the wiper. I pressed the shaft in all the way, tested and reassembled. I drilled and tapped the case to accept machine screws, and now all workd fine.

If anyone does this and has a rivited case, try to just shave the rivet head off in order to allow the cover to be removed. Then drill the appropriate sized hole for the screws you're going to use. I used a Dremel tool with a grinding attachment. It took some time, but left the case in good shape for tapping new holes.

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