This is a variant of Nick Foley's motor corner design (https://www.youmagine.com/designs/motorcorner)  but made for the back left part of the Ultimaker. Also a bit easier to print due to the upper part being completely flat. I wanted to make it a bit sturdier to eliminate potential vibration. The installation procedure should be self-explanatory. I will add a more detailed description later. Please note that this design assumes you have removed the MAX endstops from your printer. Don't be afraid to do so, they're not of much use anyway. :)