Trolley Brake???

Use it to hang your head set on.

 

You can hang your headset on it if it's on the dash. I manage to hang my ball-peen hammer on mine to hold it down to check my stop lights when it's light out. Some will tell you you can use it in an "emergency" or in some icy/slick stopping situations ... I've been driving 20+ years on and off and never used them to stop or in an emergency situation.

 

Its handy for manipulation of trailer wheels when sliding tandems.

Its also useful for a quick brake on slopes when stopped at traffic lights.

And on icy roads, if you yank on it, you can inspect your trailer as you go down the road.

(The last suggestion will be emphatically denied by myself in a court room)

 

Back in the day if you were starting from a stop on a steep hill you would use it to keep you from rolling backward. Also if it is located on the dash as small knife stuck in it will hold it down to check your break lighs on your tractor and trailer.

 

Also if your an owner operator and pulling someone else's trailer you can use it to stop and save your breaks. Now I have never done this.... lol

 

Yep...in 20 years, the only thing I ever used it for is to slide my trailer tandems. That way, the only brakes that are "on" are on the trailer, and if you have a spring-load sliding system, you can easily rock the trailer and release immediately once the pins give.
Using the trailer brakes (red knob) will deflate the air bags, and there is significant hesitation during brake release.

 

If you're behind schedule you can pull it down hard. This way the load gets there before you.

 

Some of us sitting at a truck stop in Sacramento joking about using the trolley brake as a jake brake. I joked that I just did it going through Salt Lake City. One of the drivers along with his wife, happened to have to swap trailers with me. He called the company and said he and his wife almost got killed because I wore out the trailer brakes. When he turned around and realized I overheard him on the phone; he and little wifey got beet red faces and abruptly ran to the truck and left. I didn't care enough to even comment to him and never heard anymore about it.

 

Ah yes, the trolley brake, Johnson rod, "johnny bar", I'm surprised trucks still have that. Years ago, I drove a Mack, and there was so much slop in the 5th wheel, at a stop light, before I took off, I'd pull the trolley brake, so it wouldn't slam. I've heard on slippery roads, if the wagon gets out of line, you could pull the trolley brake to get it back in line, but that is risky business. If you have your own truck, but pull someone elses wagon, you can use it to save your truck brakes on gradual slowdowns or down hills. I pulled RR cans for 5 years with my own truck, and used the trailer brakes almost all the time, (except in panic stops, of course)and never did a brake job on my truck. Nowadays, it's probably good for sliding tandems, but companies are wary of trailer brakes wearing out and truck brakes not, as using the trailer brakes to stop is not the recommended practice.