Don't try to turn the threaded adjuster sleeve. The slot shown in the picture above is there to keep it from turning so the star wheel can move it in and out. If you try to force it to turn, the bracket on the backing plate will be damaged. Use a hammer and punch to turn the remains of the star wheel
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!