Sidekick 747 printhead wobble

I’ve been using the Sidekick 747 for a few months and the prints are great. However, last week I noticed that on the initial layer the hotend is lightly dragging, which is causing print failure. With the z axis raised there is a vertical wobble. This is not side to tside but up and down. The gantry wheels are a little loose. I have looked for instructions on how to adjust them but I can’t find any.

Ideas on what the problem really is or how to adjust the wheels would be very helpful

Assembly for the gantry can be found here:

OHAI: Open Hardware Assembly Instructions (

I’d check that everything looks right according to those instructions, but it sounds like you may have a wheel with a flat spot from being too tight and/or not being moved enough. Flat spots can be worked out by just moving the wheel enough back and forth to let it even back out, or you can buy a new wheel and install according to the linked instructions.