There are plenty of sources for new/rebuilt hydrovacs. Betting your life on a home-brewed brake system on a rig that big is like drawing to an inside straight- - - -not a wager I'd want to make. Either fix it right or make it yard art!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!