Chevy van 30 Four winds


I’ve got a 7.4 Chevy and towing a car get about 15 check brakes aren’t binding urgently
As I just put it through an M.O.T, I did check that all the wheels, turned (Nearly) freely, they are not "Binding". Perhaps I will get the "Carbs" checked, but have to watch the cost's (Mechanics, are charging just too much now!) Thanks, Daybreaker.
PS: I am not that certain, that the fuel consumption, is what I said. I will give it an accurate check, by filling the fuel tank, right to the top of the filler tube, do 15 miles, and see how many liters, it takes to fill it, to the same point.