1938 Buick Special Windshield Wiper Motor

[likeold]

Windshield wipers goes up 1/3 of the way then stop and stay there, when I shut them off they slam to the down position. Tried taking the arms off thinking maybe they weren't assembled correctly but even without the arms the shafts do the same thing. Its almost like the motor can't do a full rotation if that's the way it's supposed to work and something is stopping it from going around.

Edited November 27, 2021 by likeold (see edit history)

[Bloo]

You'll just have to look inside and see if something is jamming in the linkage. Also, I believe 1938 wiper transmissions (the pieces that goes through the cowl) have a chain inside. I imagine something could jam up there. You may just have to dissconnect the linkages and see if you can move them for a full wipe by hand without any jam up. You could also try the wiper motor with the linkages off and see if it can do a full cycle, although it probably can with the linkage off even if it is screwed up.

 

A classic symptom of worn out wiper motor is stopping in the middle of the stroke due to internal leakage, and not being able to get far enough to switch direction. They will work disconnected, but don't have enough pull. You might be able to revive it by sucking some transmission fluid or brake fluid(?) into it. Don't over do it. Others might know more about that process, but if you get too much it is probably going to make a big mess when it vents, and brake fluid removes paint. In my experience if it stops in the middle it needs overhaul at the very least, assuming it is repairable.

 

Was the windshield wet? It probably needs to be.

 

If you have a double diaphragm fuel pump, that could be screwed up. In that case, for a test plumb vacuum directly to the wipers and try it at idle. Good luck.

 

Edited December 2, 2021 by Bloo (see edit history)

[MCHinson]

A little bit of light oil added to the wiper motor body might free it up enough to make it work correctly. Making sure you have good steady vacuum is important. This might also be a good time to consider joining the 36-38 Buick Club. The next issue of the Torque Tube II, which will go out about January 1st, 2022, has a nice technical article covering rebuilding a 1938 wiper motor.  I learned quite a bit about these wipers when I reviewed the article. I am thinking about opening up all of mine, cleaning them, and rebuilding them so that they work better.  

[likeold]

I did the Marvel mystery oil process per the YouTube I saw online and the wiper motor is working like new. The only problem is I ended up with a bunch of Marvel mystery oil on the floor in the cab, I'm surprised the motor works if it leaks fluid but all is good, I like easy fixes like this 🙂 

[EmTee]

6 hours ago, likeold said:

Marvel mystery oil

I've come to recognize MMO and WD-40 as my friends!