If the solenoid is refusing to engage the drive (maybe just a slight click) the brushes aren't contacting the armature properly. John's van had that problem at homecoming, but the rest of the starter was worn/tired/rusty enough that he chose to go with a new (not rebuilt) replacement starter.
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!