How to take the mono wiper motor apart?
 

I posted yesterday about what grease to put into the mono wiper motor, and am now realizing I have a NEW question to ask.....

How do I open the motor? I have my complete wiper arm out. There's a single screw on the back of the motor that allows the big plastic piece on top (the one you see when you approach your car) to get a bit loose, but it doesn't come off. I don't want to bust it.

The only other screw I see, is the big center bolt for the wiper arm. I don't want to take that off if I don't have to.

I read another article, but don't see anywhere where it says how to take the motor apart so you can get the old grease out, and put new in.

1991 300d 167k

Hmmm, one mechanic said....
 

I just talked with one mechanic, he said to leave that cover on, just pry it up, and put in spray lithium in there. He said taking the cover off is a lot more work.

The issue as you've described it usually is not in the in the "motor" but in the wiper transmission itself if I understand what you posted earlier. There is a gear reduction transmission to which the electric motor is attached which drives the secondary wiper transmission that actually moves the wiper arm.

For opening and servicing of either, you have to separate the two. Then you can open the gear reduction drive and access itsworm and gear or you can then open the wiper arm transmission and access the nylon gearing that moves the arm left and right as well as up and down.

Job is "done"
 

Well, I might have done the job wrong, but ....it's done.

I took the mechanic's advice, pried the top plastic part up a bit, shot brake fluid in there to clean a bit of stuff up, let it dry a bit, then shot in some lithium grease.

I probably missed 1/2 of what I was supposed to get, but the job's done now. I put the little squirt straw in as far as I could, and moved it around a lot, and did it from different sides. I put it back in, tested it, and at least for now.... it works.

BUT, tell me, how do I get that plastic top part off, just in case I need this info in the future?

I just pulled one for a member (it'll be going out in this weeks shipping) and I'll look it over for info on cleaning and greasing the transmissions.

The Howto section of the odometergears.com website has a doc on taking apart the mono wiper assembly to replace the gear.