Wheel cylinders lock up

You do not bleed brakes in an "X" pattern. You start bleeding at the wheel furthest from the master cylinder. Once that wheel is bled, move to the next furthest away from the master cylinder and so forth. Doing it in and "X" pattern would leave air in the lines.

abs systems do not lock on the brakes
they release the brakes when the wheels stop spinning and when the wheels start turning again apply the same brake pressure as before the wheels stopped spinning
check the proportioning valve to the rear brakes to ensure that it is not acting as a one way valve and that is causing the problems
if the compensating port in the master cylinder for the rear wheels is blocked that also will lock the rear brakes

Yes master cylinder and maybe ABS sending unit. Also is there a sound of an air leak it may also be your brake booster

Sounds more like brakes, Possible springs or wheel cylinder.

It could be a proportioning valve, and there's also the chance that the portion of the master cylinder that operates the front brakes is going bad. Have you had a pressure check done on the front brake system? Also, some vehicles have a variable proportioning valve, so that when the vehicle is loaded, it allows more pressure to the rear brakes. These can sometimes stick in place, causing the fault that you describe. Hope this helps you out.

The piston is binding in the wheel brake cylinder, perhaps a bit of rust in the cylinder.
Inspect it, replace wheel brake piston and maybe the cylinder if you can't make it "smooth".

You possibly have air in your lines. When you bleed them you need to start at the rear passenger, then rear driver, then front passenger and then front driver. If you are certain you have no air in the line then you have a bad brake hose/brake line. Replace this and your problem should go away. If not then the culprit should be the distribution or master cylinder. I hope this helps.

Start with right rear then left rear,then right front then lft front,Would rebleed at master cylinder 1st.

1- brake system low on fluid,
2- improperly bled (air in lines).
3- Master cylinder (applies equal pressure to all 4 cylinders) is bad.

You have a bad master cylinder my friend, all the braking force is going to the rear hence the lockup, the front brakes most likely don't do anthing, all mdern brake systems are split, so you have at least 2 wheels working, in effect the car has 2 master cylinders in one unit.