I have a 97 pete 10 wheel dump that used to be a regular tractor. When i originally purchased it i noticed that when loaded i had very little braking power, but when loaded and towing a trailer I had normal braking power. I have a caps that I put on the air lines to the trailer gladhands(when not towing a trailer) and if i depress both tractor and trailer brake buttons the brakes are fine. I have ran like this for many years. I have learned that a regular tractor without trailer, the air to rear wheels is decresed to prevent lock ups, now that the truck is a dump, it needs full air to rears all the time. What is the name of the valve and where is it located to change to convert from "tractor" to "truck"? Im afraid someone else will drive the truck and not push the red button in and have little brakes.