The brake booster on a GMC uses vacuum power that the engine generates to give a power assist to the braking system. Unfortunately, the brake booster is not a serviceable unit. If the booster fails, then the old booster has to be removed from the truck so that it can be replaced. Once you have the old booster removed, then you have to install the new booster. Installing a new booster should take about 30 minutes to do.
Things You’ll Need
3/8-inch ratchet and socket set, Open-end wrench set, Brake booster, Factory brake pedal clip