How to Test a Vacuum Brake Booster on a Tahoe

The Chevrolet Tahoe is a full-sized SUV that was introduced during the 1995 model year. As with all modern vehicles, the Tahoe is equipped with power-assisted brakes, and the vacuum booster is a vital component of the power braking system. Any problems with the vacuum booster can mean that a tremendous effort will be required on the part of the driver in order to slow or stop the vehicle. Fortunately, testing the vacuum booster operation is a simple task that drivers can preform for themselves.

Instructions

1

Park the vehicle, turn off the engine and pump the brake pedal a few times to use up any residual vacuum in the vacuum booster. Depress the brake pedal and hold it down. Start the engine. The brake pedal should drop about 1/4 inch. If this happens, it indicates that the vacuum booster is functioning properly.

2

Run the engine for a minute or so. Stop the engine and slowly pump the brake pedal four or five times, waiting a couple of seconds in between each pump. The brake pedal should depress to a slightly higher position with each pump, indicating that the booster is air-tight, and the booster check valve is working properly. If there is a leak in the booster or the check valve, then the brake pedal will stop at the same high position with each pump.

3

Start the engine and allow it to run for a minute or so. Depress the brake pedal and hold it down. While holding the brake pedal down, stop the engine. Keep holding the pedal down with steady pressure for about 30 seconds. If the pedal does not slowly rise during this time, it indicates that the booster is not leaking, and the check valve is working properly.