how to remove motor from hotpoint wm79?

I HAVE A HOTPOINT WM79 AND NEED TO CHANGE THE BRUSHES (ITS AN FTP MOTOR AND I HAVE ALREADY PURCHASED THE CORRECT BRUSHES) I'VE REMOVED THE WIRING LOOM 'PLUG' AND THE BOLTS SECURING THE MOTOR BUT IT (THE MOTOR) WILL NOT COME AWAY FROM ITS 'SWINGING ARM' MOUNTING ON THE DRUM. THERE IS A PLASTIC SECURING RING ON THE END OF THE 'ARM' AND ALTHOUGH I GUESSED THIS MUST BE REMOVED I AM WONDERING IF THIS RING MUST BE BROKEN TO REMOVE IT AND THEREFORE DO I NEED TO PURCHASE A REPLACEMENT. I HAVE LOOKED ON INTER-NET FOR THE ANSWER BUT WITHOUT SUCCESS SO THOUGHT I'D GIVE 'HOWTOMENDIT A TRY