ANET A8 Y axis on ball bearings - smooth and light !

My ANET A8 had been delivered with a defective LM8UU linear bearing. it had a lot of friction, was very noisy and eventually lost 2 balls I found on the floor...

Moreover, the design of the Y axis is somewhat overconstrained with 4 linear bearings which are quite difficult to align properly. But , as the Y plate is quite flimsly, the idea to remove one LM8UU is not good... The good idea is to keep 3 points to guide the plane plus 1 another one using the flexibility of the Y plate to absorb th