[Kube]

. Is this a china wheel cylinder problem?[/QUOTE]
It's possible. Some repop cylinders had the fluid return hole drilled in the wrong spot and the rubber would stop atop it - not allowing the fluid to return.

I might suggest when this happens, go quickly to one wheel (at a time) and loosen the hose at the cylinder a bit. If the pedal becomes "friendly" right away, you know the issue is in that cylinder. Repeat this for the other side.

From your post, might it fair to assume the back brakes are releasing?
If all of the brakes are locking up, I'd check the rod adjustment at the master cylinder. If the stroke is too long, the fluid will not be allowed to return to the master.