The GMC CCKW

I have dismounted, cleaned and greased wipers motors endless number of time, cleaned pipes, exchanged all rubber hoses and still one wiper is barely working with other not working at all. Please any advice regarding quality of grease for wipers, I have used suspension and graphite grease so far.

I have the same problem on my Dodge. Need a soluce.

Vacume wipers can be a real problem at times. It is imperative that the actuating device inside the wiper not be worn to the point that the vacume is leaking by. If it is there is little one can do unless you can get a new re-build kit. I picked up several old WWII used Trico wipers one time and checked out five of them before I could get two that worked well enough to put on my truck.
I have always used a very light oil, such as sewing machine oil.

Trico used a light viscosity grease. I would use GAA if I were to service a motor, but once the surface of the paddle is worn, there is nothing that can be done. It is best to send the motors out to a professional rebuilder like Mr. Ficken in New York and get them back in NOS condition. Approx $100.00 each and worth every penny.

I concur with Joel, I have used Ficken, done right the 1st time, no problems since
Vacuum wipers-the first "intermitent" wipers