Symptoms of a Bad Brake Booster

Symptoms of a Bad Brake Booster

Because of the prevalence of disc brakes, power-boosted braking systems now come standard on nearly all new automobiles and recent-model used vehicles. Disc brakes are not self-energizing like drum brakes, so they require a power brake booster to keep pedal effort reasonable for all drivers. But like any human-made device, power brake boosters can go bad.


Booster Failure
The primary symptom of power brake booster failure is a high, hard pedal that requires greater than normal pedal pressure to stop the car. You may also notice that it takes a much longer distance than normal to stop your car The high, hard pedal and longer stopping distance mean you are not getting power boost.

Proper Function
A properly functioning power brake system should provide power assist on first application of the brakes every time, with normal pedal travel, pedal pressure and stopping distance. However, if your brake pedal is low, spongy, requires pumping or fails under steady pressure, the brake booster likely is not at fault. These are indications of other serious problems in your braking system that require prompt attention.

Testing Booster
Most power brake systems in autos are vacuum-based, using the difference between engine intake vacuum and atmospheric pressure as their power source. To test your brake booster, pump the brakes several times with the engine off to deplete stored vacuum. Turn on the engine while pressing lightly on the brake pedal. You should feel the pedal fall away a bit and then become firm, but not hard. If you feel nothing at the pedal when the engine starts, your brake booster is not functioning.

Another Test
Booster problems may indicate failure of the booster unit itself or problems in the vacuum system that powers the booster. A vacuum system problem may leave you with only partial boost, according to SouthernRods.com. To test for vacuum problems, start the engine and run it to medium speed, then turn off ignition and take your foot off the gas. Wait about a minute and a half and then apply your brakes. You should feel the vacuum boost on at least two brake applications. If you do not, you may have a vacuum system leak or bad vacuum check valve.

How to Remove a Brake Booster From the Brake Pedal in a Tahoe

How to Remove a Brake Booster From the Brake Pedal in a Tahoe

The Chevrolet Tahoe has been popular among soccer moms and big families for years. Over that time, they've become fairly advanced, including features like electronic throttle control and a tighter turning radius. The brake pedal of the car connects to the brake booster at the top of the pedal assembly, and although it's not a difficult process to remove the linkage, getting to it can be a bit complicated. In this case, the project vehicle is a 2003 Chevrolet Tahoe.

Things You'll Need
Flashlight
Flat head screwdriver


Instructions
Open the door and look underneath the dash with the flashlight, following the brake pedal up from the floor to the linkage at the top of the mount. There is a round bar that comes off of the top of the pedal, with a wired switch and the booster linkage bolted to it. Reach an arm up there with the flat head screwdriver to access the metal clip at the end of the bar.

Place the flat head screwdriver between the clip and the pedal, and twist it to open the clip. This clip looks like a clamp, and the end of it covers the bar to keep the linkage in place. By opening the clip, you can then push it up vertically and pull it off of the bar, which will allow you to slide everything else off of the brake pedal.

Slide the brake switch off of the brake pedal. If you have to, you can unplug the wiring from the switch using your hands. Then, place the flat head screwdriver between the brake pedal and the booster linkage and pry it off of the round bar. This may be difficult to do, but the flat head screwdriver should help provide extra leverage.