Don't have an answer for you on the brakes. Those brake systems were unique to the TW30 and TW35 tractors. I have never worked on one, and I don't have the manual nearby to look at.
The manual attached is what you need to troubleshoot your dash. At 66 pages, it is almost as thick as the IT manual you were looking at. I can scan some pages for you if you'd like and sent it to you via pdf. Leave your e-mail open if you'd like it.
Foam your chime all you want.