What is an engine brake?

A compression release engine brake, frequently called a Jake brake, is an engine braking mechanism installed on some diesel engines.
When activated, it opens exhaust valves in the cylinders after the compression cycle, releasing the compressed air trapped in the cylinders, and slowing the vehicle.

The term Jake brake, which properly refers to the Jacobs brand of engine brakes, has become a genericized trademark and is often used to refer to engine brakes or compression release engine brakes.

My engine brake will not turn on

Generally, if your brake has stopped working entirely, you have an electrical problem. This is most likely a failed switch (probably a fuel pump or clutch switch). You can usually confirm this by hot-wiring the brake, bringing battery power directly to the solenoid leads (with the engine at idle).

Be sure to disconnect the existing leads to the solenoids so that you do not damage your control system.

If the brake does not operate when hot-wired, you may have a solenoid failure. If the solenoid is actuating but the brake is not turning on, the problem is probably mechanical.

Your engine brake dealer should be able to help you locate appropriate troubleshooting information for your engine brake.

Where can I get replacement parts for my engine brake?

Looking for engine brake replacement parts? Please visit www.pacbrakeoem.com or call Pacbrake directly at 800-663-0096 for further assistance.

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