The machine is a Ferris 32" Hydrocut. The left front caster doesn't move as freely as the right side, there is obviously a problem with it. And I don't mean the actually wheel, it's the part that turns. I've taken it off, cleaned it and re-greased, but it still feels too stiff, makes it difficult to steer the machine. Is there anything I can do? Or should I just take it back to the dealer?