⬢The bag with fasteners includes M3x20 and M3x18 screws make sure you won't mix them! Pay attention to the instructions, when to use the M3x20.

⬢Keep the magnets apart in a sufficient distance. They can break each other!

⬢The hotend for MK2.5S needs a shorter PTFE tube compared to the MK2/S (more info How to trim PTFE tube - Original Prusa printers). Make sure you have changed it.

⬢Pay great attention to the cable management, if you miss some important step you would need to disassemble the extruder.

⬢This bag includes extra fasteners. Don't worry if you finish with few unused screws and nuts.

⬢Take two M3nS nuts and insert them in the Extruder-body. Make sure both are all the way in.

Ensure correct alignment using the Allen key.

⬢Secure the nut using an M3x10 screw. Tighten the screw just slightly, later on we need to add the P.I.N.D.A. sensor.

⬢Take two M3n nuts and insert them in.

Use the screw pulling technique.

⬢Take the smaller magnet (10x6x2) and insert it carefully in the FS-lever. Majority of the magnet will be hidden inside the printed part.

⬢Insert the FS-lever in the body.

⬢Secure the part with a M3x18. Tighten it, but ensure the lever can move freely.

⬢Insert the bigger magnet (20x6x2) in the Extruder-body, it will stick out:

⬢Take the printed part Adapter-printer and insert the steel ball.

⬢Roll with the ball to all sides to ensure smooth movement.

In case of any rough surface, remove the ball and clean the inside of the printed part.

⬢Place the printed part together with the steel ball in the Extruder-body. The surfaces of both parts should be almost aligned.

⬢Extruder motor (1x)

⬢Extruder-motor-plate (1x)

⬢M3x10 screw (2x)

⬢Take the Extruder-motor-plate and secure it using two M3x10 screws. Use the cable as a guide to properly orient the part.

⬢Resist the temptation to place a screw in the third hole! Leave it for later ;)

⬢Rotate the shaft as in the picture. Flat part must in the direction of the arrow.

⬢Slide the gear on the shaft, the lock screw must be facing against the flat part of the shaft. Tighten the screw slightly.

⬢There is a "channel" for the filament inside the printed part. Align approximately the teeth on the gear with it.

⬢Don't tighten the screw just yet. We will align it properly first. See the next step.

⬢Take a piece of the 1.75 filament. You can use the bundled one on a spool, don't use the black nylon, which is too thick. Straighten the filament as much as possible.

⬢Place the filament along the path and align the gear properly.

⬢The filament will be always slightly bent. Use it anyway for the initial alignment.

⬢For a final check replace the filament with an Allen key. Bear in mind, the key has slightly different size than the filament.

⬢Tighten the screw slightly to temporarily fix it, we will make the final check and tightening later on. Be careful, you can strip the thread.

Don't use any glue to fix the screw in place, you won't be able to release it, in such case you might have to replace the entire motor.

⬢Extruder-cover (1x)

⬢M3nS nut (1x)

⬢Slide the nut all the way in.

Ensure correct alignment using the Allen key.

⬢Leave the second slot empty, we will use it later.

⬢Hotend for MK2.5S (1x)

⬢M3x40 screw (2x)

⬢M3x10 screw (2x)

We will use some screws later, so keep them around.

⬢Take two M3x10 screws and insert them in the holes. Doing this now makes the assembly slightly easier, but both holes are shallow and the screws might fall out. If this happens, you can continue without them and put them back later on (you will be noticed). Also note, that in few upcoming pictures the screws might be missing.

Hotend assembly was completely reworked from MK3 to avoid bad placement. Also any future maintenance is much easier.

⬢Place the hotend next to the Extruder-body, see the grooves in the printed part, which are in the shape of the hotend.

⬢Correctly placed hotend. Cables should point in the direction behind the hand, we will align them in the next step.

⬢Place the Extruder-body with the hotend on the box and make sure the cables are pointing down.

⬢Place your finger temporarily on the longer magnet and place the extruder motor assembly on the Extruder-body. The Bondtech gear might pull the magnet out while assembling parts together.

⬢Make sure both parts are aligned.

⬢Place the Extruder-cover on the Extruder-body. Again, make sure parts are properly aligned.

⬢Insert two M3x40 screws, you've prepared earlier. Tighten them, but be careful, they are slightly longer, than the thickness of the entire assembly.

Place the extruder aside for few steps, we need to prepare another part. Leave it on the box to prevent damaging the cables.

⬢X-carriage (1x)

⬢M3n nut (2x)

⬢M3nS nut (4x)

⬢IR-sensor cable (1x)

⬢Take both M3n nuts and using pliers (or screw) push them in the X-carriage, then using a screw from the other side, pull them all the way in.

⬢Don't forget to remove the screw.

⬢Take all four M3nS nuts and insert them in. Ensure correct alignment using the Allen key.

From now on, keep in mind the nuts are inside, avoid rotating the X-carriage "downwards", or the nuts might fall out.

⬢Take the IR-sensor cable and locate the end with the smaller connector.

⬢Place cable in the X-carriage, use the small printed overhangs to keep the cable inside.

⬢The distance between the connector and the X-carriage should be around 15 mm (0.6 inch). We will adjust it later.

⬢Guide the cable through the slot, remember this path, we will use it for other cables as well.

The IR-sensor cable colour might differ from yours, but the assembly procedure is the same ;)

⬢Grab the X-carriage and place it onto the back of the extruder assembly as shown in the picture.

⬢Make sure the motor cable follows the channel both in Extruder-body and X-carriage. In the X-carriage the motor cable will follow the path of the IR-sensor cable.

⬢Turn the extruder to the other side and if needed insert the second M3x10 screw. Don't tighten the screw, we need to adjust the IR-sensor cable.

⬢Prusa IR-sensor (1x)

⬢M2x8 screw (1x)

⬢M3x40 screw (1x)

⬢Place the IR-sensor on the top of the Extruder-body and secure it with the M2x8. Make sure the black plastic "u-shaped" part is facing down.

Tighten the M2x8 screw, the sensor shouldn't be able to move, but be careful the PCB isn't indestructible ;)

⬢Connect the cable, mind the correct orientation of the connector and wires.

⬢Leave a slack behind the sensor like in the picture. Don't create too big loop as it might interfere with the frame. If needed adjust the length by gently pulling/pushing the cable.

⬢Ready? Ok, check once more no cable is pinched and tighten both M3x10 screws installed previously.

⬢For easier fan installation, remove temporarily the black wire from the cable bundle and release at least one loop. Then tie the bundle back, see the picture.

⬢Before you move to the next step, take an Allen key and GENTLY PUSH the motor cable to the channel to create space for the fan cable.

⬢First, create a loop on the cable. Make sure the black protective wrap is close to the edge of the fan. See the picture.

⬢Place the fan on the extruder and proceed in the following way:

⬢Extruder-idler (1x)

⬢Bondtech WITHOUT the hole for the lock screw (1x)

⬢Bearing (2x) might be stuck inside the gear

⬢Shaft (1x)

⬢M3n nut (1x)

⬢M3x40 screw (2x)

⬢Idler spring (1x) place the spring on the screw

⬢Take M3n nut and place it in the Extruder-idler.

Use the screw pulling technique.

⬢Insert the pulley in idler as shown in the picture.

⬢Slide the shaft through the idler and pulley. Use reasonable force or you will BREAK the printed part.

⬢Place your finger on the bearing and ensure it can rotate freely.

⬢Place the Extruder-idler in place and secure it using a M3x40 screw.

⬢Don't tighten the screw too firmly, it serves as a shaft for the idler. Check that the idler can rotate freely.

⬢Use the M3x40 screw with the spring to introduce tension to the Extruder-idler.

Hold the Extruder-idler on the other side, until the screw reaches the nut.

⬢Since there is only one screw, you need to introduce a large force. The head of the screw, should be aligned or slightly below the surface.

⬢Take the M3n nut and insert it all the way to the support. It is crucial!

Use the screw pulling technique.

⬢Place the support on the extruder and ensure the inclined part is facing "down" (towards the nozzle).

⬢Secure the support using an M3x10 screw.

⬢Insert M3nS nut in the Fan-shroud, all the way in.

Ensure correct alignment using the Allen key.

⬢Mount the Fan-shroud to the extruder, secure it using an M3x20 screw. Don't over tighten the screw, you can break the plastic casing. Also make sure the fan can rotate freely.

⬢First, slide the fan in the Fan-shroud and make sure it is aligned properly.

⬢Second, fix the fan in place using one M3x20 screw. Tighten carefully, or you will damage the fan's casing.

⬢Turn the extruder around and insert the M3n nut. No need to pull it in, we will use the screw.

⬢Place the remaining M3x20 screw from the other side and tighten it, but carefully, or you will damage the fan's casing.

⬢Guide the cable according to the picture in the channel. Bend it slightly towards the extruder. DON'T stretch the cable!

⬢Insert the zip ties in the X-carriage like in the picture.

⬢Lower the X-axis at about 1/3 from the top.

⬢Turn the printer with X-axis motor and PSU facing towards you. LCD is on the other side. Align the bearings similarly to the picture. The exact position of the lower bearing doesn't matter for now.

⬢Place the extruder on the bearings, the top couple must fit perfectly. Make sure the X-carriage with the "belt inserts" is facing towards you.

⬢We will adjust the lower bearing later on.

⬢Tighten and cut the zip ties.

⬢Place the cables on the P.I.N.D.A. sensor side over the lower smooth rod and push them back in the channel.

⬢Place the cables on the hotend fan side over the lower smooth rod and push them back in the channel.

⬢Align the bearing, so it fits nicely in the X-carriage

⬢Guide the X-axis belt through the X-end-idler, around the 623h bearing with the housing and back.

⬢Continue with the belt through the X-carriage.

⬢Guide the X-axis belt through the X-end-motor, around the GT2-16 pulley and back.

⬢Before you continue to guide the belt through the X-axis, please release two M3 screws on the X-end.

⬢Rotate the X-axis motor as indicated towards the frame.

⬢Insert the flat part of the X-GT2 belt into the X-carriage as in the second picture.

Use a screwdriver or the smallest Allen key to push the belt in.

⬢Using right hand rotate the motor to its original position and hold it (tension is applied to the belt).

⬢Using two fingers on your left hand push the belt together. Very small force should be needed for bending the belt, BUT the belt shouldn't be bent by its own weight before being pressed with your fingers, it must be straight.

If you are struggling to rotate the motor back into position, the belt tension is too high.

⬢Depending on the belt being under or overstretched, adjust the amount of the belt in the X-carriage.

⬢When done, rotate the motor to its original position and tighten the M3 screws again.

For the following step we recommend getting a white marker, but you can also trim the belt without it.

⬢Measure the part, which must be trimmed and gently take the end of the belt away, from the X-carriage, but make sure at least 3-4 teeth are still in the X-carriage, as you don't want to lose the tension. If possible make a mark, where to cut the belt.

⬢Ensure again your mark is in the correct position and the belt is still stretched.

⬢Using pliers cut the belt and push it inside X-carriage. Use screwdriver or Allen key, if needed.

⬢Black nylon filament 50 cm / 19.7 inch (1x)

⬢Using the pliers cut one end of the filament to create a tip.

⬢Check the tip is similar to the third picture.

⬢Locate the hole for the NYLON filament. Using the smallest Allen key ensure there are no obstacles inside.

⬢Using the pliers insert and twist the NYLON filament in the slot. Hold the extruder with your other hand.

⬢To check if the filament is seated properly, gently pull it with your hand. The X-axis should bend a little, but the filament must remain in the slot.

⬢If you have issues, try to adjust the tip on the filament.

⬢X-carriage-back (1x)

⬢Cable-holder (1x)

⬢M3x40 screw (1x)

⬢M3n nut (2x)

⬢Take the M3n nut and place it in the printed part (all the way in).

Use the screw pulling technique.

⬢Tighten the X-carriage-back and the cable-holder together.

⬢Secure the screw by tightening the nut all the way to the surface. Do not use excessive force, as you might crack the printed part.

⬢Push the cables from the Extruder THROUGH the X-carriage-back start the print fan and P.I.N.D.A. sensor cables.

⬢Next, add IR-sensor cable, then the extruder motor and hotend fan.

⬢Carefully insert the nylon filament and then slide the X-carriage-back towards the X-axis.

⬢M3x10 screw (4x)

⬢Use all four screws and tighten the X-carriage-back.

⬢Zip tie (5x)

⬢Textile sleeve 13 x 490 mm (1x)

There are three textile sleeves in the package, use the largest one (both diameter and length).

⬢Open one end of the textile sleeve and slide it on the cable bundle leading from the extruder. Don't forget to include the nylon!

⬢Leave the cables from the Hotend out for now.

⬢Length of the first wrap should be slightly longer than the cable-holder part.

⬢Gently twist the sleeve to make it smaller and tighter around the cables, orient the sleeve's seam downwards, then slide the sleeve towards the extruder.

⬢Ensure the cable-holder is properly oriented and at the end of the screw.

⬢Take 3 zip ties and tighten the textile sleeve to the holder.

⬢Now, add the hotend cables to the cable-holder.

⬢Once the hotend cables are included, use two zip ties. Tighten them and cut remaining parts.

⬢Open the textile sleeve and insert the cables from the hotend.

⬢Finish wrapping all cables in the sleeve.

⬢Insert the M3x10 screw in the printed part.

⬢Note the orientation of the part, arrow shows the side, which will be in contact with the extruder.

⬢Locate the hole on the right side of the X-carriage.

⬢Mount the Endstop-block and tighten the M3x10 screw. Mind the correct orientation of this part!