How to know when drive belts need to be re-tensioned and is it difficult to do


I have less than 1000 hours on my M300, but I want to make sure I’m maintaining the machine correctly. Is it difficult to make sure the belt tension is correct? If anyone has any advice, I’d appreciate it.



Please check out this manual. Please focus on the step 4.

Kind regards



I have many troubles when I falow the “Axes Maintenance” guide…
In fact, my printer is very unprecise… As you can see in the pictures, it is very bad, but I already print in the past the same file and it was good…
But the thing is that I found the belt a little bit loose, so I have decided to fix it by following your guide.
But now the belt is good but my printer can’t go in some corner of the platform and stay stuck on the corners.
So I remake all the steps of the guide and I have found that on X and Y axes, if I put the jigs well on one side, the opposite side is not good, that mean that my axes are not paralle…
So how can I solve it ?


Hi, @FMVP.

As you’ve noticed that axes are not properly aligned, you should perform maintenance with jigs.
I also suggest that you clean the nozzle or replace the hotend, as quality deterioration can be caused by wear of these parts too.


Hi Marta, thank you,

But the thing is that I already perform the maintenance with jigs. twice !!! But the point is that when I align the left side properly with jigs, if I verify if the right side is well align after this, the right side is not good even if the left is good. And it is the same with the front and back side…
So do you have more advice to perform better the maintenance with jigs ???


Not a problem.

You need to properly align the blocks - they should be placed on parallel belts teeth. Make sure that you don’t push the block too much, as it can cause further misalignment. You can try to place one shipping clips on each axis, so that you won’t move the block too far on the belt.
If that doesn’t help, please record the process or take some pictures showing the misalignment after the maintenance.