The brake booster is an essential component of the modern braking system. It is responsible for providing the extra force needed to stop the vehicle, and it works by using vacuum pressure generated by the engine. To understand how this fundamental component works in the braking system and some tips to help you diagnose and determine if the electric brake booster is the primary source of your problem, let's take a closer look. The vacuum-assisted brake amplifier needs at least 16-18 inches of mercury (Hg) at idle to operate effectively.
To test the amplifier's function, install a vacuum gauge and check the pressure gauge while driving. You'll need to know how much vacuum you have at idle, as well as what the maximum vacuum is during deceleration. Most power brake systems work well with a 15-inch vacuum manifold, which a motor with a standard camshaft easily supplies at idle. However, engines with long-lasting high-performance cams keep the valves open longer, resulting in idle vacuum readings well below 15 inches.
This reduces amplifier assistance, resulting in a hard brake pedal.To test the vacuum and check that there is a minimum of 18 inches of vacuum pressure and that there are no vacuum leaks, start the engine and maintain moderate pressure on the brake pedal. When the brakes are released and the engine is running, there is a balanced atmospheric pressure on both sides of the diaphragm and no boost pressure can be generated. As you pump the pedal, the pressure will become firmer, indicating that the brake booster is not leaking.The pump turns on when it reaches a vacuum level of 18 inches and shuts off as soon as it reaches 23 inches of vacuum. Therefore, it is essential to install this cartridge between the vacuum port of the intake manifold and the power brake booster in order to store the greater vacuum supplied by the engine during deceleration.
With so much vacuum pressure flowing through the system, this can even cause brake fluid to end up inside the brake booster, as well as damage the master cylinder gaskets.When the brake pad material is almost completely worn out, the sensor will turn on the brake warning light to let the driver know it's time to check and replace the brakes. If air flows in both directions or air cannot be expelled, it means that the valve is damaged and that you'll need to replace your power brake booster. If you're not comfortable performing these tests, it may be a good idea to have a professional mechanic come to your location to perform an on-site inspection of your brake system.In conclusion, understanding how many inches of vacuum does a brake booster need is essential for proper operation of your vehicle's braking system. The pump turns on when it reaches a vacuum level of 18 inches and shuts off as soon as it reaches 23 inches of vacuum.
To test if your power brake booster is working correctly, install a vacuum gauge and check that there is a minimum of 18 inches of vacuum pressure and that there are no vacuum leaks.
