Bobtail braking

Yes. A valve was added to the system, starting around 1988? It is supposed to help prevent wheel lock up.
Some I find to be a larger problem than touchy brakes.

 

This is on the dash of my Kenworth truck in my avatar. 1995 model.

 

It's more difficult to stop bobtailing then load with 80,000. When bobtailing you have to many tires on the ground for the weight of the truck. You basically will just slide on all tires vs the tire having grabbing power and stopping power. The only tires that really have good traction is the steer tire. That's why is take more room to stop bobtailing then of you had 80,000

 

Modern trucks reduce brake effectiveness when not hooked to a trailer so as to prevent locking up the brakes.

 

Yes, I almost had a bad wreck just last week no tailing. The braking system is designed to stop with a load.

 

I don't think they reduse the brakes. We now have antilock brakes. That was one of the problems we had before ABS. When bobtailing you would lock up the drive tire and you just slide/ can't stop because their no weight to keep all those tire on the ground to grab. You only have the steer tires. Now we just have ABS so the drives don't lockup then keep spinning but still don't grab.

 

Decal says it all.

 

I've got that same decal in my 93 KW t-600.

 

All the kool kats roll with no front brakes