Truck Repair: Air Wiper motor for R Model MAck, mack truck, van don

Question
Where can I locate a picture or diagram for the wiper motor?
R Model Mack 1977    Motor is not working and I believe I am missing an air line.  Any info would help. Thanks

Answer
Hello Marty,
I have a 75 R769 at work, with air wipers.
I also have all the books for it, although I have never read the wiper part, but I bet I have it.
If you want to call me there tomorrow, cal 580-429-3007 or 580-429-3221 and ask for Van.
Don't explain too much about it to the person that answers...it is a wildlife refuge.
Just say you need to talk to Van about something on the Mack truck.
If I happen to be out somewhere, leave a name and number, and I will try to find out something, and call you back.

Van