What is the Johnny bar for?

How about preventing freezing trailer brakes. A light hand on the Johny bar, (about a mile before parking), engages the trailer brakes enough to warm them up and evaporate any moisture that will freeze in cold weather.

The reason they say not to touch it is because it doesn't have the same kind of feedback as the foot brake. It is very easy to lock up the trailer brakes with the Johny bar. All trucks with a Johny bar should have a brake pressure gauge so you can see how much brake you are applying before you can feel it.

The last two company trucks I drove did not have a Johny bar. It made me uncomfortable. I had to resort to using a screwdriver between the brake pedal and dash to check my brake lights. Had to just "trust" that if the parking brakes held during a tug test, then the service brakes must work also, instead of actually verifying that they do.

 

Nope, didn't have anything about it on the permit test (Florida) and was never covered during school either, other than to say "don't use it"... My truck now doesn't even have one.

 

That's too bad. I believe it is a necessary piece of important safety equipment. However, without proper training it can be very dangerous. So instead of training, they (big companies) just quit ordering them.

 

There are countries that have outlawded them. To many accident with them because off improper use.

 

I use it when I park on the fuel island at the Peelot to go in and buy my 5 gallon bucket of soda and case of Krispy Kreme donuts. Works well! All the suckers in a hurry to get fuel pull up behind, thinking you're leaving! Then they wait as I go to the bathroom, look around the store, and wait in line for an hour to pay

 

Johnny bar is also called trolley bar.I've used it as a second brake when moving tandems.Also always make sure the Johnny bar is in the up position otherwise your trailer brakes could catch on fire.Its very easy to accidententally hit with your arm.So if you see your trailer brks smoking pull over let them cool and first thing to check is if the Johnny bar is down.

 

It would make sense. Instead of the tractor brakes slowing you down with a load behind them and inertia pushing you foward, the trailer brakes would kinda pull back on the tractor. Like reins on a horse.

 

I used to use the trolley with the Jake all day long cause it was easier to change trailer brakes than tractor brakes

 

Johnny bar is used to check if you have air to the rear trailer when pulling sets and triples. If you open the valve on the last trailer air comes out. No air means no brakes.

Also used to check brake lights.

Used to give driver behind you a sea sick feeling when you are in stop and go traffic. Let truck roll a foot, pull bar, , trailer rocks and sways.

 

Who is Johnny?