Small Engines (Lawn Mowers, etc.): Ryobi 725r trimmer head clutch repair

Question
I have three power heads I have dissemble cleaned and reassembled several times with no luck getting the clutches to work. I've used break cleaner, have tried very light tri-flow on clutch wings only after rust removal on one of the power heads. I am concerned the clutch slips inside the housing cup if they are expanding with centrifugal force. I've even tried a light pipe thread sealer on inside of one of the cups to get grip. Cables are not broken and square cable seems to be tight in cup throat. Power heads all run great just no torque at receiver heads for multiple attachments. I am stumped but persistent. Any suggestions would be much appreciated.

Answer
There should be nothing inside the clutch drum or on the clutch...no fluids at all.

I have seen a lot of these models and the clutches are fairly reliable.  Are you sure the shaft and cable are fully seated in the clutch drum?  Is the clutch drum square hole stripped or rounded out?

Can you use a power drill to turn the inner cable to see if the trimmer head spins?

Eric