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How An Engine Brake Works

What is an Engine Brake?

The Jacobs Engine Brake (also known as the "Jake Brake®") is a diesel engine retarder that uses the engine to aid in slowing and controlling the vehicle.  When activated, the engine brake alters the operation of the engine's exhaust valves so that the engine works as a power-absorbing air compressor.  This provides a retarding, or slowing, action to the vehicle's drive wheels, enabling you to have improved vehicle control without using the service brakes*.  This conservation results in reduced service brake maintenance, shorter trip times, and lower total cost of ownership.

Watch our "How a Jake Brake Works" video below to see the engine brake in action and find out how to operate a Jake Brake.

How a Jake Brake Works


Jacobs Operator's Manual

To learn more about how the Jacobs Engine Brake works, download the complete Operator's Manual.  The manual contains useful information on how to operate a Jake Brake.  Topics include instructions on using driver and engine controls, special instructions on driving on various road conditions as well as using the engine brake on vehicles with ABS, cruise control, and automatic transmissions.   The manual also includes the recommended preventative maintenance and service schedule to ensure proper operation of your Jacobs Engine Brake.  

Download Operator's Manual
To learn more about the benefits of the Jacobs Engine Brake and the new technologies we offer, visit our technology page


 *The Jacobs Engine Brake is a vehicle-slowing device, not a vehicle-stopping device.  It is not a substitute for the service braking system.  The vehicle's service brakes must be used to bring the vehicle to a complete stop.

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Our Story

Although the Jacobs Engine Brake has been on the market since 1961, the need for it was terrifyingly demonstrated to its inventor Clessie L. Cummins, some thirty years earlier. In August of 1931, himself, Ford Moyer, and Dave Evans driving a Cummins diesel powered Indiana truck from New York to Los Angeles...

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