Update: 11.09.2018 Please check https://www.thingiverse.com/thing:2829855
This is a better solution but you can still use two of my designed parts, so I did.

The issue was that often the two T8 threads were not syncronize and I had to do again manually with a fixture. Now I use only the one original stepper, a belt and some minor parts.
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Original starts here:
This three parts I designed for making a second stepper to lift-up the second side of the Z-bar.
The parts I had to buy was:

1. T8 Treadbar with 500mm length + follower ( Mother)
2. Flex coupling to put between stepper and threadbar
3. Two identical stepper because necessary. Hard to get the original, so I bought 2 new
4. Longer screws to mount the Winkel were the mother for following the T8 thread sits.

I bought some parts at Amazone and some at ebay. The T8 threadbar came with mother and coupling and ballbearing. I believe the costs are about 45 € for all exclude the self printed parts.
I used PET g material and that is my favorite printing stuff.

Creality3D CR-10

0,1mm

30

Wall thickness 1,2mm

I'm not a professional with that but I like to make things work. I know there are better design but it is my idea and it worked. The second motor to lift the extruder seems not to be a
" Must have" like others but in my case I like to have it more strong. The prints are until now not visible better but now I would have no problem to change the extruder with an other, (more havier one).