Flushing Brakes

[papercu]

I bought a old (1975?) truck that was a ex-Air Force base truck and then a ex-Forestry truck and got it home yesterday.
The engine cranks and seems to run fine BUT no brakes, one of the reservoirs is dry so I assume I have a leak(s) somewhere in that part of the system.
I would prefer not to dump any DOT-3 on the ground if I can help it, is there anything more Eco-friendly?
Seems as if I heard alcohol was used when DOT-3 was converted over to BSF for flushing lines but didn't find that in the TB.
Any suggestions or just go with the brake fluid and hope for the best?
Anybody know the year? TIA, Wayne

 

[WillWagner]

It has that mid 70's Dodge look, you are probably close on your guess. No tag in the door jamb?
I just flush with the fluid I plan on using and use a pressure bleeder 'till it is clean and clear.

 

[papercu]

O, Boy I think I know now why it was turned in, my brother does most of the mechanic work and just told me the front reservoir is milky looking and chunky so it is a good bet that before it was discharged from service, it had the BSF change over and then someone added DOT-3. Wayne