The Subaru Outback's hydraulic braking system requires the occasional purging of the DOT-3 fluid used to apply pressure to the friction surfaces. This fluid can be bled from the lines one wheel at a time, in an alternating pattern, by the average backyard mechanic in one hour.
Raise the Outback with the floor jack and place the jack stand onto the frame rail. Do not place the jack stand onto the suspension or body.
Remove the wheel by turning all of the lug nuts counterclockwise. Pull the wheel from the hub and store it away from the work area.
Open the hood and locate the master cylinder. It is against the driver's side firewall, and is a small white reservoir with a black cap. Unscrew the cap and check the color of the brake fluid.
Place the drain pan underneath the brake assembly. Attach the small hose to the purge nipple, located on the back of the caliper. Place the other end of the hose into the drain pan.
Open the brake line by turning the purge nipple counterclockwise until fluid begins to come out.
Pour fresh fluid into the master cylinder while depressing the brake pedal. This could take two people to do properly.
When the fluid coming out of the nipple is golden yellow and free of air bubbles, close the nipple by turning it clockwise. Remove the hose from the purge nipple.
Remove the drain pan and replace the wheel. Turn the lug nuts clockwise, with an alternating pattern.
Lower the Outback from the jack stand with the floor jack.
