Potrice

I replaced the rear wiper motor on my ML about 7-8 months ago (and again 2 years prior). Anyways, I ordered a new one from Rockauto and everything was smooth this winter. Well today the ba$tard seems to be dying again. The rear wiper seems to struggle and sometimes gets stuck halfway through the rear window.

Of course, the motor is still in warranty (good for 12 months and I’ll only have to pay 25$ dollar shipping to get the replacement) but this is getting annoying. I made sure to clean everything everytime I installed a new motor in (remove the rust on the bolt and put lubricant to prevent everything from seizing). What could be killing my rear wiper motor every ~12 months?

peter2772000

Is there some sort of water-proof seal outside of the motor shaft that's missing/damaged?
It makes no sense and can't be bad luck. If it is, I don't want to be standing next to you in a thunderstorm *wink*

Potrice

I removed the motor and when I took it in my hands, water was gushing everywhere from the inside...I called MB and I’ll change the grommet that sits between the rear window and the rear wiper motor. Mine was all rusted through, so I guess water was going in...

Did you ever change yours? Rear wiper motor that is.

Potrice

Fixed the issue by changing the rubber grommet. Now there's no water getting inside and frying the motor.

peter2772000

Awesome and no, never an issue on ours. We only had 20k km on it when we bought it almost 2 years ago though