SummaryI have recently started having some problems with my EZstruder, on my Kossel Pro, after hundreds of hours printing. It began with the odd missed layer or section that meant scrap prints - most annoying. What was happening was that the small, ballrace was slipping sideways off the filament every now and again causing the feed to stall. I have to admit to doing most of my printing with the clear cover removed for ease of maintenance. However, even with the cover replaced, there was enough movement to allow the bearing to keep slipping off the filament. It appears the red, lever arm was getting fatigued and the thin section, around the pivot, was just too thin and was allowing far too much movement. I started by wanting to modify the EZstruder bowden clamp but it was impossible to drill it out 4mm, to allow the PTFE tubing to pass through, without destroying the thread. I re-designed it to allow the EZstruder, aluminium, bowden clamp fitting to be used but this still meant the end of the tube could not be placed right next to the pinch wheel and hobbed driver. However, this design is a very good replacement for the standard EZstruder if you are having similar problems. This version is black in the photos. The final design is the white one that uses the E3D, push in, bowden clamp. I designed both versions as direct replacements for the EZstruder even though I didn't need to as I have placed my extruder on one of the uprights. In my opinion, this is one of the best mods I have made, along with replacing the original tube with a shorter, PTFE one. TXT files added are STEP files from the original design. Just change the .txt to .step and import into your favourite 3D CAD program. Thanks must go to Taylor of MatterHackers for posting the original mod from which I took the inspiration - thanks, Taylor.Post-PrintingImportant tip for printing the white one.Make sure you push the PTFE tube right through the extruder body till it protrudes where the hobbed wheel and bearing will be. Then trim off the tube to match the printed part. Doing this enables flexible filament to be used on a bowden machine as there is nowhere for the filament to bunch up.How I Designed ThisJust added a shorter, more compact version. It uses the same parts as the other version, just the back plate changes. Sonny has just pointed out that the extruder will not fit directly to a stepper as it needs a recess in the back to accommodate the boss on the stepper. I will add another file for printing a spacer if you need to attach directly to the stepper. Spacers added 31/10/15