Tecnam P-Mentor pilot reported during landing roll the aircraft pulled to the left uncontrollably. Pilot stopped aircraft on runway where maintenance personnel hit the rudder with a mallet to unlock the brakes.

Narrative

The wind was 190 at eight; and the approach to Runway XX was going well. The touchdown was smooth and on center; and only a minor crosswind technique had to be held in. The nose wheel touched down; and we began our rollout on the Runway. As we were rolling; the plane suddenly started pulling to the left. I applied the right rudder and no change. I applied even more right rudder; and still no change as we pulled more to the side. I opted to use breaks as necessary as we were going to go off the Runway had I not. After we stopped; I tried to spin the aircraft to the right using power and the right pedal. The aircraft was unable to move and was stuck in position. I immediately told the Tower we could not get off the Runway and were having issues. Tower called ops and sent out a few trucks to help. We shut down and waited for them to arrive. Maintenance hit the rudder with a mallet to unlock the brakes. We then taxied behind an Ops vehicle to the FBO. As we taxied; I noticed that the right pedal seemed to have minimal input and did not allow full turns like it should. We parked at FBO; got out; and called our flight school.