https://horsegossip.proboards.com/thread/140797/brake-fluid
Also possibly useful:
https://s6dc2dc82dd3d959c.jimcontent.com/download/version/1549548021/module/8252183115/name/Peterbilt%20Model%20210-220%20Operator%27s%20Manual.pdf
And
https://www.kelberg.com/downloads/DAF-CHASSIS-DRIVER-MANUAL.pdf
Ehdhdg, June 2022