How do you Change a tractor trailer brake cystem to a streight truck?

Answer 1

Just leave it as is, and don't push in your trailer air when you drive. If you're referring to the Johnson bar, it can be changed to engage the tractor brakes instead of the trailer brakes, but it would probably be more hassle than it's worth. The only applications I can think of where one would actually benefit from having the Johnson bar engaged the power unit brakes are dump trucks (particularly, those dumping asphalt or concrete into pavers) and roll-off container trucks. Otherwise, there really is no use for it, unless you have something like a Mack R or RD model, where you have to pull lightly on the Johnson bar to engage the differential lock (but in which case, the Johnson bar would already be set up to engage the brakes of the power unit).