Is there a way to convert this to work behind a 1 ton truck?

? You have hydralic assit now and want vacumn ? What brand truck? If this is what you want find 150 series with vacumn booster and switch, but not recomend at all. You will lose alot of braking assit/braking power by doing this .

Are you referring to this setup on a trailer ? I have a friend that is in the Boat Sales Business and he had Vacuum ports mounted on the back of His 92 Chevy 1 Ton Gas Dually and it worked fine.He was pulling a 39 Cigarette in Traffic and it stopped without any problem.

Yes it was the trailer I was talking about, thanks that was what I needed to know. Do you know how much it cost to do that, just aprox.? Thanks again