The brake booster helps you slow down or mark your vehicle safely by multiplying the power you employ to the brake pedal. Without the booster, you would have to step very hard on the pedal and your safety on the road would be compromised. This is the main reason car manufacturers recommend periodic inspections of the brake system.
Type of Brake Boosters
The booster is a cylindrical unit with an internal diaphragm or piston that mounts between the firewall, inside the engine compartment in front of the steering wheel, and the brake master cylinder. Depending on your particular Dodge truck year and model, engine vacuum or hydraulic pressure activates the booster whenever you apply the brakes.
Hydraulic boosters are common in diesel engines, since they produce less vacuum compared to regular gasoline engines. However, some gasoline engines use this system as well. In a hydraulic unit, fluid from the steering pump provides the pressure to push an internal piston.
Inspecting a Vacuum Booster
Visually check the booster-housing unit and the vacuum hose between the booster and the engine for wear and damage. A check or one-way valve connects the vacuum hose to the booster. Inspect the valve for physical damage as well.
With the engine off, depress the brake pedal about eight times to drain any residual vacuum inside the booster. Then, rest your foot very lightly on the brake pedal as you start the engine. As vacuum enters the booster, you should feel the brake pedal moving downward a bit. Otherwise, there is a leak in the system or the booster is damaged and unable to hold vacuum.
Some boosters may be rebuilt while others are sealed and have to be replaced with a new or rebuilt unit. Consult your car owner's or vehicle service manual for more information on your particular model, if necessary.
James E. Duffy, in Modern Automotive Technology, recommends consulting your car owner's or vehicle service manual to test or repair the hydraulic booster since the specific procedure may change from one vehicle year and model to another.
Look for signs of leaks at the connections and run your fingers along the lines to find hidden leaks from view.
Also, check the steering pump fluid level. Low fluid in the pump will fail to operate the booster properly.
