x axis moves freely to right but offers resistance when going left
I have two year old prebuilt i3. This problem started happening after I changed the nozzle. It was my first nozzle change and I torqued the extruder a bit until I figured out how to get the nozzle off. After about 10 minutes of printing well the printer crashed and then missed some steps. When powered off I found that the head moves freely to the left but offers much resistance going right. The resistance is uneven. In some places leftward movement was normal. In others I had to push fairly hard. I left it alone for a couple hours and now it's moving freely again.
- I don't see groves in my rods.
- No squeaking.
- The belt looks fine.
- I lubed everything and for what its worth there is a bit of black deposit on one side of the top rail.
I'm preparing to rebuild the x-axis movement but I'm not sure what's the problem. Is this likely a bad linear bearing, a pulley bearing, or possibly the stepper? I'm willing to replace all but don't want to waste my time with a bigger job than necessary.
Its unlikely to be anything other than your bearing.
But just step by step diagnose - If you loosen or remove the belt and move the axis and its still stiff then that rules out the stepper. Also the only proper way to lubricate the bearings is to remove them, clean them out and repack with a suitable grease.
You can temporarily use a light oil (like gun oil or sewing machine oil) applied to the rods and work the bearings back and forth in the area to get some oil past the dust seals on the bearings but that's only a stop gap measure. Working the grease that is supplied with the recent kits past the seals doesn't work well, its too thick to get much past. Its ok applied to the inside but as I say that requires disassembly.