If U hook up the hoses correctly and the brakes work in the truck being towed, U do not need to press the peddle, the air from the front truck makes the brakes work, as for towing , it can and has been done, as for doing it without practice, ?It is very different and if it gets away from U there will absolutly be NO way to bring it back, And well thats scary.U can't have someone in a towed vehicle on a public road, and it is not safe, its bad for the hobby to take chances, Since u are asking, If U can hook a 5 tonner to Your deuce and run it and feel it first, BEFORE U go,And lock up the wheels once or twice!well then U have at least done some homework, as for learning on the road itself I for one say don't do it, My 2 cents is DO NOT pull a 5 ton with a deuce unless U have the experience . Know all the things that can and will go wrong will, I never would have done it in my first days as an MV big iron owner, BUT after 9 years of towbarring and with the big truck experience under my belt when i was Young running tandems, , I now have done it, BUT with more caution !realizing I would never going over 40 and not everysecond feeling my brakes could stop me in a pinch . and prepared to abort any time i would feel nervous,Its a very serious endeavor.What condition are the brakes in the deuce, ? they are working now so U think they will do it??, I did not tow any vehicle untill i have Had all my wheels pulled bearings repacked and wheel cyclinders checked and some replaced, they can be going without u knowing it and if one blows while u are towbarring u are done, I have found most deuces have at least one wheel cylinder weeping waiting for the overload,U can only see that with the wheels OFF! These trucks are to old to take that kind of work safely without proper maintanence, sorry my 2 cents is alot in this, I do alot of prep all year long on my trucks so I hope they are safe,Alot of guys i know jump into there deuces and race to a parade, never having wheels off never tightening all the bolts, expecially the jack shafts! I do know a guy who paid for it once, had his deuce for 5 or so years the jackshaft let go broke apart the tranny came up thru the floor, He was very lucky not to have lost a leg!after it happened...said whats a jack shaft? ...Randy