⬢This guide will take you through the replacement of the Z-axis linear rail on the Original Prusa XL.

⬢All necessary parts are available in our eshop prusa3d.com.

This guide is for both Z-axis linear rails on the XL printer.

This procedure requires printing the necessary tools. See the next step for more information.

⬢Lubricant accumulates mainly in the linear rail channels on the linear sides.

⬢T10 screwdriver or key

⬢4mm Allen key

⬢2.5mm Allen key

⬢Alignment Tool

⬢If you have loaded the filament, unload it from the hotend. On the screen, navigate to Filament -> Unload Filament.

⬢Remove the filament from the hotend.

⬢Unwind the filament to the spool and remove the spool from the printer.

⬢Cooldown the printer, navigating to Preheat > Cooldown.

See if the side of the Z-axis linear rail you will change has an antenna, spool holder, or filament sensor. In case any of those is present, follow the instructions below to remove it.

⬢Release the screw securing the spool holder and remove it from the printer.

⬢In case your printer has an antenna on the side where the linear rail will be replaced, unscrew the antenna by hand and remove it.

⬢Auto home your printer. Navigate to Control -> Auto home.

⬢Move the Z-axis 5 cm under the Nextruder. Navigate to Control -> Move Axis -> Move Z.

⬢From the rear side, turn the power switch OFF (symbol "O").

⬢Unlug the power cable.

The following step is necessary only if the filament sensor is on the same side as the Z-axis linear rail that is being replaced.

⬢With two fingers, push the black collet on the rear of the filament sensor assembly.

⬢At the same time, gently pull out the extruder PTFE tube from the filament sensor assembly.

⬢Using the 2.5mm key, loosen the screw holding the frame-rear-cover.

⬢Carefully slide out the frame-rear-cover.

⬢Turn the printer to the left side if the Z-axis linear rail to replace is on the left side.

⬢If the Z-axis linear rail to replace is on the right side, turn the printer to the right side.

⬢Take a look at the bottom of the printer and locate:

⬢Remove both covers from the printer.

The bottom of the printer is ready.

⬢Locate the rear extrusion cover 354mm, and remove it.

The printer is now ready for releasing the motor.

⬢Using a T10 screwdriver, remove two M4x10rT screws and remove them. Do not throw them away! We'll use them later.

⬢Using a T10 screwdriver, remove the indicated two M3x12rT screws from the heatbed frame. Do not throw them away! We'll use them later.

⬢Slide the bed-frame-mount to the middle of the linear rail.

⬢Using a T10 screwdriver, remove four M3x8rT screws to release the Z motor. Do not throw them away! We'll use them later.

⬢Hold the Z-axis motor with your hand. Don't pull out yet!

⬢Grab the threaded rod with your other hand.

⬢Gently pull out the motor from the Bed-frame.

Follow this step if the Z-axis linear rail to replace is on the LEFT side of the printer.

⬢Locate the area indicated in green.

⬢Loosen 4x M3x8rT. Do not throw the screws away, we'll use them later!

⬢Leave the other 2x M3x8rT tightened.

⬢Remove the fixed arm from the rest of the linear rail.

The linear rail is ready for final removal from the aluminum extrusion.

Follow this step if the Z-axis linear rail to replace is on the RIGHT side of the printer.

⬢Using the T10 screwdriver, loosen the M4x8rT and after that remove the rotary arm.

⬢Using the T10 screwdriver, loosen 4x M3x8rT to remove the square mount.

The linear rail is ready for final removal from the aluminum extrusion.

The Z-axis linear rail is attached to the printer frame by 7x M3x8 screws.

⬢Using the short part of the 2.5mm Allen key, loosen 7x M3x8 screws. Do not throw them away, we'll use them later.

⬢The second picture shows a detail of the area marked in green with the rest of the printer, with the linear rail highlighted.

⬢Carefully remove the Z-axis linear rail.

⬢For the following steps, please prepare:

⬢Linear rail (1x)

⬢M3x8 screws (7x)

⬢Centering tool (1x)

Follow this procedure if you are replacing the Z-axis linear rail on the left side of the printer.

⬢Insert the centering tool between a pair of M3x8 screws. Start with pair 1. Tighten the two screws next to the centering tool slightly, using the long side of the 2.5mm Allen key.

⬢Repeat this procedure for the other screws, apart from the one closest to the heatbed assembly.

Follow this procedure if you are replacing the Z-axis linear rail on the left side of the printer.

⬢The first picture shows a detail of the area closer to the heatbed. The screw closest to the heatbed assembly is tightened against a T-nut.

⬢Remove the green safety pin. Tighten the screw using the long side of the 2.5 Allen key.

⬢Repeat the full procedure with the centering tool for all pairs and for the screw closest to the heatbed in the indicated order. Tighten the screws fully but carefully, using the long part of the Allen key.

Follow this step if the replaced Z-axis linear rail is on the left side.

⬢Locate four threaded holes on the linear rail carriage.

⬢Place the arm-fixed in place.

⬢Using the TX 10 screwdriver, tighten the four M3x8rT screws.

⬢The other two M3x8rT screws are already tightened.

Follow this procedure if you are replacing the Z-axis linear rail on the right side of the printer.

⬢Insert the centering tool between a pair of M3x8 screws. Start with pair 1. Tighten the two screws next to the centering tool slightly, using the long side of the 2.5mm Allen key.

⬢Repeat this procedure for the other screws, apart from the one closest to the heatbed assembly.

Follow this procedure if you are replacing the Z-axis linear rail on the right side of the printer.

⬢The first picture shows a detail of the area closer to the heatbed. The screw closest to the heatbed assembly is tightened against a T-nut.

⬢Remove the green safety pin. Tighten the screw using the long side of the 2.5 Allen key.

⬢Repeat the full procedure with the centering tool for all pairs and for the screw closest to the heatbed in the indicated order. Tighten the screws fully but carefully, using the long part of the Allen key.

Follow this step if the replaced Z-axis linear rail is on the right side.

⬢Locate four threaded holes on the linear rail carriage.

⬢Place the square-mount in place. Using a TX 10 screwdriver, tighten 4x M3x8rT screws.

⬢Place the arm-rotary in place. Using a TX 10 screwdriver, tighten the M4x8rT screw.

⬢Using one hand, take the Z-axis motor and keep it in a row.

⬢Using the second hand, insert gently the Z-axis motor back through the Bed-frame.

⬢Move the Z-axis motor to the side through the Bed-frame.

⬢Insert four M3x10rT screws into the four holes in Z-motor-mount.

⬢Tighten the screws with a T10 screwdriver.

⬢From the bottom side of the heatbed:

⬢From the upper side of the heatbed:

⬢Manually slide the bed-frame-mount towards the heatbed.

⬢Secure the Bed-frame-mount to the Bed-frame with two M3x12rT screws using a T10 screwdriver.

⬢Take a look at the bottom of the printer.

⬢Insert the motor cable in the extrusion. Make sure it goes perpendicular from the motor to the extrusion first.

⬢Insert the Extrusion cover 243mm. Push it and slide it through its length.

⬢Push the Z-motor-cable-bottom-cover into the frame.

⬢Insert the motor cable in the extrusion.

⬢Insert the Extrusion cover 354 mm.

⬢Turn the printer to the right side on its feet.

⬢If the replaced Z-axis motor was on the other side, turn the printer to the left side on its feet.

⬢Carefully slide in the frame-rear-cover.

⬢Tighten the M3x12 screw using the 2.5mm key.

⬢Connect the filament sensor cable to the filament sensor assembly.

⬢Move the filament sensor assembly to the top of the extrusion and align the M3nEs nut so that it aligns with the opening on the filament sensor assembly.

⬢Attach the filament sensor to the M3nEs nut using the M3x12rT screw and T10 screwdriver.

⬢Insert the PTFE tube from the extruder into to the first collet on the rear of the filament sensor assembly.

This step is necessary only if you have the antenna on the side of the printer where you replaced the Z-axis linear rail.

⬢Locate the Wi-Fi antenna connector on the right rear corner of the printer.

⬢The antenna can be rotated around and bent in two directions.

⬢We recommend pointing the antenna straight upwards.

Original Prusa XL comes with two versions of the spoolholder. Each version has a slightly different parts and different procedure.

⬢Spool-holder-slider (1x)

⬢Spool-holder-base (1x)

⬢Spool-holder-mount (1x)

⬢M5x85 screw (1x)

⬢M5nEs nut (1x)

⬢Carefully turn the printer so that the side with the Wi-Fi antenna and side filament sensor faces you.

⬢Insert the M5nEs nut into the front support extrusion (with the orange plastic cover). Insert the side with the spring (metal plate) first, then push the nut inside.

⬢The M5nEs nut is free to move, you can adjust the position as you want. But remember, the nut must be slightly pushed in to smoothly move. Anyway, we recommend approximately the same position as you can see in the picture.

⬢Insert the spool-holder-base into the spool-holder-slider and push it through a little through the part.

⬢Attach the spool-holder to the spool-holder-mount.

⬢Insert the M5x85 screw into the spool-holder-assembly.

⬢Carefully turn the printer so that the side with the side filament sensor is facing you.

⬢Insert the M4nEs nut into the front support extrusion (with the orange plastic cover). Insert the side with the spring (metal plate) first, then push the nut inside.

⬢The M4nEs nut is free to move, you can adjust the position as you want. But remember, the nut must be slightly pushed in to smoothly move. Anyway, we recommend approximately the same position as you can see in the picture.

⬢Locate pins two pins on the spool-holder-base and line them with the rails in the spool-holder-slider.

⬢Insert the spool-holder-base into the spool-holder-slider and push it through a little through the part.

⬢Insert the M4x12 screw on the longer side of the 3mm Allen key.

⬢Insert the 3mm Allen key with the M4x12 screw through the assembled spool holder to the prepared hole in the spool-holder-base.

⬢The M4x12 screw has to protrude through the spool-holder-base.

⬢From the rear side, plug in the power cable.

⬢Turn the power switch ON (symbol "I").

⬢Turn the printer's front side facing you.

⬢On the screen, navigate to Control -> Move Axis -> Move Z. Rotate the LCD encoder to move the Z-axis to the bottom, until the end of the range, and observe if the movement is smooth.

⬢On the screen, navigate to Control -> Calibrations & Tests -> 4 Z Alignment Calibration and let the printer calibrate.