Can someone explain to me why some drivers keep the red one out?

Even now I never set the trl brk unless I drop the trl or parked on an incline.

 

I was taught in school not to set my trailer brakes when parking, which I still don't do

 

The service and parking brakes operate off of different brake cans/springs, my front drive axle has the parking brake can mounted on top of the service brake can.
A weak parking brake means nothing as to how well your service brakes stop the truck.

 

You already told a lie. I pull both knobs, unless parked for a short periodic time.

 

I always set both when temp is above 38 degrees. Below 38 degrees, yellow, only on flat level surfaces.

 

Don't forget to roll your trk back & forth so yap don't feezer to the ground

 

if your tractor brakes won't hold a loaded trailer. it's time for you to crawl under there and adjust them bad boys. and keep them adjusted till you can get into a shop for replacement slacks.

then you won't have to worry about how much time there is before someone gets killed.

 

On my current ProStar and the Freightliner that I had before it, the trailer/red knob automatically pops out whenever I pull the tractor/yellow knob. So you folks that set only the tractor brakes, do you hold the trailer/red knob pushed in while pulling the yellow/tractor knob?

 

I was unaware that mega junk carriers allowed their drivers to attempt this. Learn something new everyday.