how semi truck trailers don’t just roll away when disconnected from a semi truck
In: 8
Ex trucker here. These answers are kinda right but wrong.
Although air pressure does keep the brakes off, trailers have their own air tank which is supplied and filled with air from the unit (cab section).
When you park up you have to go to the trailer and pull a lever which activates the trailer brakes so you can pull out without the trailer rolling away.
The landing legs will not always stop a trailer from rolling away and shouldn’t be relied on to keep the trailer in place. They can and will bend if parked loaded on a slope with the trailer brakes off.
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