WHILE LANDING THE TAILWHEEL AIRPLANE WITH A DIRECT X-WIND FROM THE RIGHT, THE AIRPLANE SWERVED OFF THE RIGHT SIDE OF THE RUNWAY AND GROUND LOOPED. INVESTIGATION REVEALED THAT THE TAILWHEEL WOULD FREELY SWIVEL TO THE RIGHT RESULTING IN NO STEERING TO THE LEFT. THIS FREE CASTERING WAS CAUSED BY WEAR ON ONE SIDE OF THE LATCH SPRING, AND CORRESPONDING WEAR IN THE SPRING NOTCH IN THE STEERING ARM ASSEMBLY. THE RUDDER STILL HAD FULL TRAVEL AVAILABLE BOTH TO THE RIGHT AND LEFT.