Jake Brake Info

They are illegal only if there is a local law. Jakes are mainly used for steep down grades to hold the slower speeds in lower gears which keeps brakes from over heating which causes brake failure. For any where else they work great for slowing if the driver just wants to gear down. More smooth for a controled reduction in speed while air brakes lag causing the load to be jerked around more. Wear on the engine good question, but the company I worked for wanted us to use them after going up a grade because it would make the engine cool more even.

 

There are drivers that use them in rest area's at 3 in the morning. They come flying in there and wake everyone up. I think those drivers are inconsiderate to say the least!

What is the difference between an engine brake and a jake brake or are they the same?

 

They really don't have added wear. Jake Brakes is just a brand name for engine compression brakes. I believe it was named after a guy called Jacobs in the early 60's. When you go down hill without Jake brakes your foot is off the gas and and most likely resting on the brake pedal if not braking.
The compression stroke of the engine compresses air/fuel, the compressed air/fuel against the piston acts like a spring and piston momentum continues, letting the truck gain speed.

The Jake Brake opens the exhaust valve continuously robbing the cylinder of the compression stroke. The drag created by the engine with no piston compression then helps slow the truck. The rumble you hear is the piston explosion coming out the exhaust pipes
Most trucks, each cylinder has a 2nd exhaust valve and an additional lobe on the cam that is solenoid operated for engine compression brakes. This is how you can control it with your dash switch/ pedal switch and there's a switch on the clutch too.

 

I think a Jake is one type of engine brake....named after Jacob somebody!

 

I just checked. It was invented by Jacobs in 1962 and patented by Clessie Cummins.

 

im in school now and they dont teach the use of the jake brake but i got in a truck one of the instructors used and left the jake on and when i let of the gas i got scared and didnt realize it was the engine brake but felt like an idiot.

 

I've seen drivers bobtail around parking lots w/them on.

 

Just the cool ones.... just the cool ones

 

First off how a Jake works, when the piston is coming up on the compression stroke when it would inject the fuel, it opens the exhaust valve, that utilises the power it takes to compress the air, and removes the compression in the cylinder, that would help, to push the piston down. Using the Jake keeps the boost level up and the motor warm. What condo cruiser posted is how a Mercedes 906 and 4000, works, they have a separate valve in the cylinder that opens with hydraulic preasure, plus, they add the exhaust brake. The benefit of the Mercidies is they are quiet and can be used everywhere, even in posted areas, they are better in the winter because it is a steady, braking force, a Jake is a vibration, and can and do break loose in low traction situations. If you ever are going down a hill with the Jake's on and one wheel breaks loose it will spin backwards, very fast. Just a thought!

 

Someone told me that jake brakes are bad for the motor if you use them too much. He's says if you use it too much, it will shorten the life of the motor. Is this ture? It sounds bizarre