How to remove this hub?

Is that $300 each or pair. Etrailer has them for $147 each
Hub assembly

Thank you for the advice. Boy the spindle-hub costs as much as what I paid for the dolly. Oh, well.

You can add brakes but you still need a spindle so your not saving anything. If you think theres to much movement replace them, the video of the spindle link tells you how to bolt on. $300 is not a lot for new spindles.

Thank you for the replies. The movement is up-down or front-back, not in-out. Both sides move exactly by the same amount in the same radial direction. No grinding or rough rolling when I spin the wheels. If my car wheel moved to the same degree, I would replace the hub or replace the wheel.

By looking at the construction, I can tell tow dolly wheels are not designed like a car. The entire "axle" is a square bar inserted into a square pipe with plastic shims between them and 2 bolts holding the pipe to the bar. This is an older Demco model with pivoting wheel pan and hot dip galvanized. I bought this used and don't know the mileage. Previous owner knows no history, either.

I have a related question. The replacement wheel hub (Demco brand) is very expensive. For about the same price, I can add an electrical brake using non-demco parts. But how do I go about it? Once the sealed hub is removed, I will have 4 bolt holes, 2 3/8" x 3 1/8" pattern. Also there is no spindle. What can hold a hub if no spindle?

Unit bearings like that often have just a slight amount of movement in them. Same goes for the bearings in many of our trucks.

There should be 4 bolts that hold it on with that square rear flange. I would think that it should have no movement in it. Are both sides equally loose? Is the looseness in and out movement or up and down? How many miles are on it? If the miles are high it might be time to replace both of them. It may be an issue like some unit bearings in our front wheel drive vehicles, some dont have a long life.

Appears to be sealed unit. Must un-bolt from frame