Prusa i3 MK3 X-Axis Belt Replacement

Introduction

If you are experiencing layer shifting issues or having issues with the function of the X-axis belt, you may need to replace it. To replace the X-axis belt in your PRUSA i3 MK3, follow the steps in this guide. With heavy use, replacing the belt every 6-8 months is recommended. Ensure that you do not lose any of the parts or socket head screws that are removed during replacement.

What you need

Step 1 X-Axis Belt

Prusa i3 MK3 X-Axis Belt Replacement, X-Axis Belt: step 1, image 1 of 3

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Prusa i3 MK3 X-Axis Belt Replacement, X-Axis Belt: step 1, image 3 of 3

Orient the printer so that the screen is facing to the left.
Using the On/Off button, switch the printer into the Off position.
Ensure your printer is off by visually inspecting the screen. If the screen is not lit up, your printer is off.
Ensure the printer has cooled to room temperature before beginning disassembly.

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Step 2

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Orient the printer so that the screen is facing away from you.
Remove the five 2.5mm X 10mm socket head screws on the back of the extruder assembly.
Remove the back cover and pull it away from the extruder assembly. Do not put too much tension on the wires.

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Step 3

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Orient the printer so that the screen is facing you.
Loosen the 2.5mm X 18mm tension set screw.
Loosen the two 2.5mm X 18mm socket head screws on the right, holding on to the X-axis motor.
Slightly loosen the 2.5mm X 18mm pivot screw on the left. This screw will act as a pivot for the X-axis motor.
Pivot the motor to release the tension on the belt.

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Step 4

Orient the printer so that the screen is facing away from you.
Loosen the 2.5mm X 18mm and 2.5mm X 30mm socket head screws that hold the belt in. You do not need to remove these screws.
Remove the belt from the belt grips by pulling the belt towards you.
Un-feed the belt from its track. The belt should now be removed.

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Step 5

During reassembly, ensure proper tension on the belt before reattaching the back cover of the extruder assembly.
With the extruder assembly positioned in the center of the X-axis rails, press the top of the belt with moderate pressure. The top of the belt should not be able to touch the bottom of the belt.

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Conclusion

To reassemble your device, follow these instructions in reverse order. During reassembly, do not over-tighten the socket head screws. Reference Step 4 for proper belt tension.

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