You might examine the piston boot on the caliper. If it is cracked and broken, it may be allowing dirt/debris to hinder the piston action. Have you tried bleeding the brakes yet? If it was actuator related, it should affect both calipers. Removing and lubing the 2 slider pins will most likely help also. Pin torque is 35 ft lbs when re-installing. If you are not able to figure out the problem, call me on Wed @ 931-967-5101 ext 16.