Things You'll Need
Lug wrench (to remove the wheels)
Vacuum pump (optional)
Air in the brake system is a very bad thing, as the brakes will be spongy and ineffective. Air will get in the line whenever you disconnect a brake caliper from its hose or do anything else to open a passage into the system. You must bleed each brake individually at the caliper to purge all air from the system. You should bleed the brakes every year or two anyways, because the fluid can boil over time and leave air in the system as a result.
Make sure one end of the Jeep is raised and secure on jack stands and the wheels on each side have been removed. If you have been working on the brakes, this should already be done. Hopefully, you have raised the rear end first as that is the end you should start at.
Connect clear rubber tube to the bleeder valve on the right rear brake caliper. Start with this end and side because it is farthest from the master cylinder. Place the tube's other end into a container partially filled with brake fluid.
Open the bleeder valve on the caliper and have an assistant press on the brake pedal inside the Jeep. Look for a mixture of air and fluid to come out of the valve. Once all the air is purged and the fluid runs cleanly from the valve, close the screw and remove the tube.
Repeat the process for all four brakes. Move to the left rear next, followed by the right front and the left front. If you need to, reconnect the Jeep's rear wheels and lower the rear end before raising the front end and removing those wheels.
Check the level of fluid in the master cylinder periodically as you bleed the brakes. If the level drops below the needed fill line, add more fluid. Use fresh fluid, not any that you have bled from the brakes.
Start the Jeep's engine after bleeding all the brakes and press on the brake pedal - you might need to do this repeatedly to seat new brake pads you just installed. Turn off the engine and hold down on the pedal. Bleed the brakes again if the pedal sink within 15 to 20 seconds.
You can use a vacuum pump to bled the brakes also. Connect the pump's tube to the bleeder valve and create the vacuum in the pump before opening the bleeder screw. You won't need another person using the pedal this way.