What's a Jake Brake and Does It Have To Do With Less Than Jake?
Funny names aside, Jake Brakes provide serious stopping power.
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If you’ve ever heard a semi truck making an extremely loud sound while slowing down, you’ve likely heard a Jake Brake, commonly referred to as engine braking in layman's terms. The feature uses the truck’s engine and exhaust to slow down instead of the brakes. It’s an extremely useful function that helps save brakes and slow a heavy truck down safely.
Not everybody loves engine braking, though, as it can be disruptive and frightening for anyone unlucky enough to be standing nearby. Though it’s mainly for use in large trucks, jake brakes can be found on some pickup trucks, where towing heavy loads requires extra stopping power.
How do Jake Brakes work? Why do some people hate them? We’ll get into that here, as well as helping you to understand the basics of engine braking. Stick with The Drive’s grimy editors and we’ll have you up to speed in no time.
Let’s jump in.
[This article's text and photos were updated on 02/24/2021]
What Is A Jake Brake?
Jake brakes, sometimes called a decompression brake or engine brake, is a feature of some diesel engines that opens exhaust valves to the cylinders to release compressed gas and slow the vehicle. The feature is mostly used on large trucks, but has been banned in many areas because of the loud noise that it produces during operation.
Where Does the Name Jake Brake Come From?
The name Jake Brake comes from a product that, unsurprisingly, is named the Jacobs Engine Brake. The company that makes them, Jacobs Vehicle Systems, says that its system is a diesel engine retarder that uses the engine to help slow the vehicle. It alters the engine’s exhaust valve operation so that the engine acts as a power-sapping air compressor.
How Do I Know If My Car Has One?
If you’re wondering whether or not your car has one, the answer is probably no. Jake brakes are, or were, far more common on large semi trucks and vehicles that need extra stopping power. They were never intended for use on your turbo-diesel station wagon. Some modern trucks, such as a recent model of the Ford F-250 have engine brakes, but they’re becoming less common.
Why Do I See So Many “No Engine Braking Signs”?
When a large diesel truck uses its engine brake, the sounds it produces are brutal. They sound almost like gunshots, which is obviously a bad thing for neighborhoods and pretty much anyone else within earshot.
Jake Brake Terms You Should Know
Gross Vehicle Weight Rating
The gross vehicle weight rating, or GVWR, is the maximum safe weight that a vehicle can carry when fully loaded with people, fuel, and cargo. Part of the reason engine brake are more common on large trucks is because it’s exceedingly difficult to slow down a heavy load using brakes alone, and can make them wear more quickly.
A bobtail is a semi truck without a trailer attached. This can happen when a driver drops off one load and has to travel to another location to pick up the next.
The cab is the portion of a truck where the driver and any passengers sit. Think of it like your car’s interior, where there are seats, a climate control system, and a stereo or radio.
FAQs About Jake Brake
You’ve got questions, The Drive has answers!
Q. Does Jake Brake Hurt the Engine?
A. Not under normal use. The only times it will hurt the engine is when the driver allows the truck to push the engine’s RPM level over its maximum.
Q. Does Jake Brake Use More Fuel?
A. Engine braking should shut off fuel consumption, which doesn’t happen when braking normally or when shifting into neutral.
Q. Are Jake Brakes Illegal?
A. They are not illegal everywhere, but are banned in areas where noise is not ideal. Some municipalities and neighborhoods issue bans, and have signs to indicate that.
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