Just a FYI. If anyone is part of the Antique Automobile Club Of America http://www.aaca.org/
or SPAAMFAA, http://www.spaamfaa.org/
, their library has a ton of info on the Barton UA-50 pump. I am a member, and got the following info for $25 (cost of photocopying and mailing.
It's a great resource thats probably not as used as much as it should be. If your not a member, you should be, as it's well worth the membership price for the information they can provide.
Bulletin 8330-A - 4 color pages
Bulletin 8330-C - 6 color pages
Bulletin 8330-C, 2nd ed. - 6 color pages
Bulletin 8330-C, 3rd ed. - 2 pages
Bulletin 75, No. 2, U-35, U-40 and U-50 - 6 color pages
UA 50-60 Repair Parts Sheet - 1 page
Barton-American UA-50 sheet - 1 color page
Barton-American Type-UA - 4 color pages
Bulletin 75-S-1, No.1, Instructions for Mounting and Operating U-35, U-40, U-50 and U-60 - 4 pages
Instruction Manual for Mounting, Operating and Maintaining the
Barton-American Front Mounted Centrifugal Fire Pump - 28 pages