One problem related to brake disc caliper has been reported for the 2000 Subaru Outback. The most recently reported issues are listed below.
Experienced poor brake performance including increased stopping distance, vibration, and steering wheel shimmy. Inspection of right front disc brakes showed inside brake pad worn unevenly. Brake caliper is two-piston system and uneven wear was due to one cylinder not working. Situation repeated approx. Eight months later on left side and now right side shows repeat of same problem. Repair required replacement of entire caliper assembly.