When I installed polymer Igus bearings I realised that the original Y carriage plate was bent. This was causing that bearings were moving with a lot of friction. After instaling this plate (which is straight and much stronger then the original one) Y carriage started to work properly. I have alse removed the springs, because they are generating a lot of tension and properly leveled carriage works great without them. Nuts covers for bed leveling You can find here: https://www.thingiverse.com/thing:2843274
Also check my I3 Mega ULTIMATE upgrade guide! There is a lot of knowledge which may help You get the best results. You will find it here: http://bit.ly/2OVbu5Z
I'm using it with this bearing holders and Igus RJZM-02-08 bearings: https://www.thingiverse.com/thing:1062598
Three bearings are enough for the bed. I was using four for some time but three are working better, and are easier to mount properly.
You can also use my bearing holders which are great for Igus RJ4JP-01-08: https://www.thingiverse.com/thing:2791727
Y Carriage Plate: https://bit.ly/3yLzYYo
This belt mount is using M4 nuts and bolts. Use Zip-ties to lock the belt.
belt_mount_v4.stl | 691.2KB |