Tensioner Assembly Replacement


When the replacement tensioner assembly is installed, remember to use a tuner to adjust the belt tension to the appropriate setting.

Remove the Tensioner Assembly from the Belt


  • 3mm hex key
  • 2.5mm hex key

Pulley Removal Procedure

  1. Use a 3mm hex key to loosen the belt tensioner by turning it 3-4 full rotations.
  2. Use a 2.5mm hex key to loosen and remove the two set screws that hold the tensioner in place.
  3. Using the hex key, push the shaft pin through the pulley and remove the pulley from the belt.
  4. When you remove the pin and pulley, you will have 5 separate pieces.
  • 1x Pin
  • 1x Pulley (with old bearings still installed)
  • 2x convex washers
  • 1 tensioner assembly

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Replace the Tensioner Assembly

Note: Reinstalling the two washers in an incorrect orientation can damage the system. Make sure to align each washer with its convex (rounded) face inward, flush against the bearing.


  • 2.5mm hex key

Pulley Replacement Procedure

  1. Align the two washers with their convex faces flush against the pulley, then wrap the belt around the pulley. Then insert the pulley (with the washers still in place) into the tensioner assembly.
  2. Use your finger to push the shaft pin through the hole in the tensioner assembly, through the pulley, and out the other side. Ensure that the same length of pin protrudes equally on both sides of the pulley.
  3. After the pulley is successfully installed, ensure that the rest of the belt is properly routed through the idler pulleys located in the Y-axis rail.
  4. Secure the tensioner assembly by reinstalling the remaining two screws.
  5. Follow the instructions in the Adjust Belt Tension support article to tune the belt to the appropriate tension.