(apologies for only now finally putting this on the right thread, not trying to spam).
So i have managed to get one of the two rails I took apart (to adjust bearings) back together.
some thoughts on assembly / disassembly for posterity:
- this video is great - though note they thread the metal strip through the black clips incorrectly (refer to the official video on support site for this).
- if you pulled the black/white cable out more than about 2mm when extracting the motor end be VERY careful during reassembly as the wire excess gets pulled from the switch end to the motor end and has a tendency to curl as you push the motor unit back in, this risks the wire bending and touching the linear screw rod (which will quickly lead to unit failure). To pull the wire back down you will need to remove the end stop switch and pull, unless you can hook fish the wire - i tried that and found i couldn’t reliably snag it without pulling it out of the switch.
- removing the end stop switch was massive PITA - the front screw bolt is fine, the rear one is super hard - only attempt using a L shaped allen wrench/key and hold the nut with good pliers. This will take a while to get loose enough to slide the switch out, do not remove the nut if you don’t have to.
For now i am going to use the one checked unit snapmaker sent me with this unit i adjusted and re-assembled. If this doesn’t improve matters i will cycle back through the original 2 linear units (the ones with the slope, on an assumption that one of those may be good). I am not going to manually adjust the bearings again new units should be adjusted correctly from the factory.