The brake booster on a 1999 GMC Suburban provides an added assist to the braking booster, which makes it easier to stop the SUV. The brake booster is not serviceable, so if it fails, then the entire unit has to be removed from the firewall and replaced with a new one. Fortunately, this doesn't take very long to do and you can do the entire job in about an hour.
Open up the hood. Pull off the rubber vacuum tube leading to the vacuum booster on the driver's side of the firewall by hand. Unbolt the brake master cylinder from the brake booster using an open-end wrench. Pull the master cylinder off of the brake booster making sure not to kink the brake lines.
Look under the dash and locate the brake pedal connection to the booster. Remove the pushrod retaining clip using the needle-nose pliers, then pull the brake light switch and the brake booster pushrod off of the pedal.
Unbolt the brake booster from the firewall with the 3/8-inch ratchet, extension, universal joint and sockets. Go under the hood and take the brake booster off of the firewall and discard it.
Put the replacement brake booster onto the firewall. Bolt it in place with the factory hardware and the 3/8-inch ratchet, extension, universal joint and sockets. Reattach the booster to the brake pedal and put the brake light switch and pushrod retaining clip back onto the pedal.
Put the master cylinder back onto the brake booster using an open-end wrench. Push the vacuum line back onto the brake booster with your hands.
