Windshield wiper motor

[Mertz]

I removed my wiper motor, cleaned it up and put some mystery oil in it. Before adding the oil I could hear vacuum being pulled when I manually move the wiper arm mechanism. After adding the oil and using my vacuum pump I got it to hold vacuum with the gate closed. Putting my finger over the vacuum tube I could not move the arm without a lot of effort. 
 

When I apply vacuum with my pump however the arm does not move.  Am I missing something?

[Mertz]

I got the motor working today. The marvel mystery oil sat in it overnight and this afternoon I removed most of it and used my vacuum pump to apply vacuum and the motor works as it should and even returns to its rest position. 
 

I used this method before on my Studebaker after years of not having effective wipers. I now can use them and not get pauses do to low vacuum. 

[Los_Control]

I was reading your post yesterday .... I really have no clue myself.

A month ago or so I worked on my vacuum motor and pulled it out ... Like a dummy I just never checked it before pulling it out ... truck sat for 20-30 years in a field, and did not have any hope they would work. .... they seem to work just fine and stuck the motor back in.

 

Then I was wondering what a proper way to lubricate the motor as general maintenance. So basically I just thought about it and did nothing.

Maybe I will try a little MM oil myself.

[Mertz]

The mystery oil has worked for me several times.