U joint Locked is this a vac problem?

[MesserFitD]

Trying to figure out what I need to replace or test to figure out why my hub will not hold suction? The passenger side u joint rotates freely in auto but my left side is locked in. I tested for suction on the drivers side and there is nothing. Now I don't know what to to any thoughts? I had a mechanic say I need to just wrench it free with a crow bar but that seems like a bad option...