I just disassembled, cleaned, and re-lubricated my vacuum wiper motor (CSM). Chances are you are dealing with old grease at the bottom of the sweep jamming the paddle. they are surprisingly simple in construction so a couple of cell-phone pictures is enough to get it apart and put back together without trouble.
Some notes in point form:
-The funny rectangle-headed screws are easily gripped with a pair of pliers. When threading these back in, remember you are screwing into old pot-metal, so be very gentle.
-The disassembly order should be - remove the valve assembly on the back, undo the top screws, lift the top off, slide the paddle up
-I soaked the main housings over the work week in varsol to soften the baked-on dirt and grease. I omitted the plastic parts and the paddle from this, as I did not want those dissolving, and instead did my usual parts washing (Brushing varsol on it until the grease was off the part) on those.
-The paddle has two leather strips riveted together between two iron plates. DO NOT MESS WITH THE CONTOURS OF THE LEATHER - This forms your vacuum seal! If this needs to be repaired, it is best to abort, reassemble, and send to the professional with photos of what you found.
-The back of the motor has a latching, reciprocating valve. A small lever pushes the latch to one side as it nears the end of its travel, which moves a plastic cap nested on the top to redirect the vacuum.
-Because the atmosphere side of the paddle vents inside the valve latch chamber, there is a felt block here to serve as an air filter. I soaked this in varsol to dissolve the old oil, squeezed it dry, and reinstalled it.
-For lubricant, I used Permatex Synthetic Grease. I ensured the same amount of grease went on both sides of the paddle. Don't forget the upper housing will have a spot for the paddle to travel in.
-I got a couple of reproduction Trico model CSM gaskets off of Ebay, and I used a tiny bit of gasket maker to help seal the housings.
On the slide valve. the part that directs the vacuum is supposed to be rubber, and that part on mine was brittle from the years of dry-baking under a metal dashboard. I recreated the part in Autodesk Fusion and 3D-Printed it in TPU, a thermoplastic that has some rubber like properties. I'll see what happens to it over the years, but so far my vacuum motor has minimal leakage there.
I uploaded the 3D model here
