I think I need a new trailer jack, it is locked up and will not crank up or down!!  I have lubed it and it still won't turn.  I have check to see if something was stuck around the staff but there isn't.  It worked just fine Wednesday night just turned a little hard but last night I couldn't get it to turn at all.

If I replace the jack what pound jack should I get??  BPS has a 1000lb on sale for the price of a 800lb.  My jack has a circle that is attached to a side plate on the trailer, the jack roates on the circle.  Are they all(the circle) the same size?

It is a Champion trailer.

If it is a Fulton jack, call the company direct and they will sell you one and ship it to your door.

It sounds to me that your jack threads are worn out.  Trailer Jacks are so cheap these days that it's much more cost effective just to replace the one you have.  I would start with Academy Sports.  Unless you are towing a VERY large boat, any jack will do.

JigMan,  Yes, it is a Fulton jack............Do you have a phone number for Fulton?

Wal-Mart carries them.