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  1. This guide will take you through the entire process of how to disassemble the MK3S/MK2.5S/MMU2S extruder, replace the PTFE tube and assemble the extruder back. Note that the upper part of the MMU2S extruder is slightly different from the single material MK3S/MK2.5S, but the disassembly is the same as it focuses on the lower part.
    • This guide will take you through the entire process of how to disassemble the MK3S/MK2.5S/MMU2S extruder, replace the PTFE tube and assemble the extruder back.

    • Note that the upper part of the MMU2S extruder is slightly different from the single material MK3S/MK2.5S, but the disassembly is the same as it focuses on the lower part.

    • This guide doesn't work for the MK3/MK2.5 type of extruder!!! See the How to change a PTFE tube - MK3/MK2.5

    • To obtain the new PTFE tube, you have two options:

    • Buy cut and chamfered PTFE tubes from our eshop

    • Make your own PTFE tube using this guide: How to trim PTFE tube - Original Prusa i3 printers

    The link to your eshop for replacement PTFE tudes still points to the old URL https://www.shop.prusa3d.com/en/3d-print... instead of the new one https://shop.prusa3d.com/en/3d-printer-p...

    This causes Google chrome to display the following error

    Your connection is not private

    Attackers might be trying to steal your information from www.shop.prusa3d.com (for example, passwords, messages, or credit cards). Learn more

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    Jonathan Lin - Reply

    Hi Jonathan,

    this was some internal redirecting error. It is fixed now. Thanks for reporting it.

    Jakub Dolezal -

  2. Please prepare the following tools for this chapter:
    • Please prepare the following tools for this chapter:

    • 2.5mm Allen key for M3 screws

    • Needle-nose pliers for zip ties (optional)

    • Pliers are not needed, but in some scenarios, you might need them to cut the zip ties.

    • Apart from the mentioned tools, it is recommended getting a bowl or a small box for the screws and parts you will remove during the disassembly, you will need them later.

  3. Before you start it is recommended to protect the heatbed! Use any cloth or piece of fabric, which is thick enough and cover the heatbed. This will ensure you won't damage (scratch) the surface during the disassembly.
    • Before you start it is recommended to protect the heatbed!

    • Use any cloth or piece of fabric, which is thick enough and cover the heatbed. This will ensure you won't damage (scratch) the surface during the disassembly.

    • Make sure that:

    • the filament is unloaded from the hotend (remove also the spool and the spool holder)

    • the printer is properly cooled down

    • the printer is unplugged from the socket

    • X-axis with the extruder is slightly above the middle of the height (Z-axis) of the printer.

  4. In this guide, we won't disassemble the extruder completely. Thanks to the new design it is enough to release the screws and move the plastic parts slightly apart. Release and remove the M3x14 screw from the hotend fan. Release and remove the M3x20 (M3x18) screw from the hotend fan. Note that the fan-shroud might fall off.
    • In this guide, we won't disassemble the extruder completely. Thanks to the new design it is enough to release the screws and move the plastic parts slightly apart.

    • Release and remove the M3x14 screw from the hotend fan.

    • Release and remove the M3x20 (M3x18) screw from the hotend fan. Note that the fan-shroud might fall off.

    • Leave the other two screws holding the hotend fan in place. No need to remove them.

    • Release both screws, but don't remove them. We will use them to hold the extruder parts together.

    • Release both screws, but don't remove them. Just make sure they won't block the motor from moving.

    I’m not entirely sure what it means to “release” a screw. I had assumed that the threads should remain engaged, but is that the opposite of the intended meaning?

    Gary Bringhurst - Reply

    Hi Gary, that means loosen the screw.

    Filip M - Official Prusa CS -

    The picture below shows that the screws need to be totally disengaged or removed. You can’t remove the motor otherwise. It must be a language thing between countries. If you want to loosen the screw then say that, but not release.

    Brad - Reply

    Hello Brad, thank you for your comment, we’ll check the wording here.

    Martin L. - Official Prusa CS -

  5. Before you move any parts, make sure there is enough slack in the extruder motor cable!!! If not, you have to cut the zip ties on the textile sleeve, open the box with electronics and make sure the motor cable is free to move. Carefully move the extruder apart. First, pull the motor, then the lower part with the print fan.
    • Before you move any parts, make sure there is enough slack in the extruder motor cable!!!

    • If not, you have to cut the zip ties on the textile sleeve, open the box with electronics and make sure the motor cable is free to move.

    • Carefully move the extruder apart. First, pull the motor, then the lower part with the print fan.

    • Create a gap similar to the picture. Align the printed part holding the motor with the edge of the fan frame.

    • Reach for the hotend and incline its upper part towards the motor, it should slide out.

    • If the hotend is still stuck inside, release the screws more and increase the gap between the printed parts.

    • BE EXTRA CAUTIOUS with the hotend cables!!! You can break them! Use a small force to pull the hotend out. Don't bend the cables.

    I have followed the instructions exactly on my MK3s and the motor and the fan (pink above) does not come apart. I have checked and double-checked but nothing gives.

    Suggestions? Solution?

    ken tompkins

    ken tompkins - Reply

    Hi Ken, perhaps you haven’t loosened certain screws enough.

    Double check both screws holding the extruder cover (marked in green), mentioned in the previous step.

    Filip M - Official Prusa CS -

    Did no one else have a problem with the magnets??? Total pain with them wanting to come out

    Paul Deutsch - Reply

  6. For the following steps, please prepare:
    • For the following steps, please prepare:

    • PTFE tube for MK3S/MK2.5S/MMU2S (1x)

  7. No need to place the hotend in the horizontal position like in the picture. It is better to leave the hotend next to the extruder.
    • No need to place the hotend in the horizontal position like in the picture. It is better to leave the hotend next to the extruder.

    • Press the black plastic collet.

    • Remove the PTFE tube from the hotend.

    • Throw this old tube immediately to the nearest trash bin to avoid installing it back by accident ;)

    The filament inside my extruder jammed so bad, I could do nothing to get it out. So, I thought that I could replace the PTFE tube as that is where I believe the jam to be located. However, I now have a big problem in that I can’t pull the tube out because I think there is some filament jammed in the tube or hotend that is prohibiting the tubes removal. No I am truly stuck. I can’t get the filament out of the tube, I can’t get the tube out of the hot end, and I don’t know what to try next. VERY FRUSTRATED!

    paul klevann - Reply

    Hey Paul, don’t worry - there’s an easy way to solve it. Simply loosen the heatsink from the heatbreak, so it can be taken off. That way you can pull the heatsink off and expose the PTFE tube, which should then be easily removable.

    Filip M - Official Prusa CS -

    Ok, how do I loosen the heatsink from the heatbreak? I do not see a way to separate them…

    paul klevann - Reply

    You can simply twist them - the heatsink should be hand-tight. If it got stuck, you could use pliers (although very carefully not to bend anything).

    Filip M - Official Prusa CS -

    I am currently dealing with the same problem. For me, it took constant, moderate pressure with the pliers, along with reverse pressure underneath it with a spanner small enough to hold down the black collet.

    Jake Askeland - Reply

    I’m stuck at same mentioned by Paul and I’ve already removed the heatsink. The filament jammed at the hotend tip. Trying to pull the filament but really very tight. What next can I do without accidentally breaking any cables at the hotend.

    Mahadar - Reply

    Hello Mahadar,

    Try to heat the hotend up a little, so that the filament softens.

    Martin L. - Official Prusa CS -

    Martins recommendation is a good one. For me it was sufficient to set the nozzle temperature to 120 degrees [1] and while heating up, I was able to pull out the tube including the piece of PLA that got stuck. I didn’t try lower temperatures before.

    [1] Settings => Temperature => Nozzle => 120

    Felix -

    @Felix. Heating up to 120 like you said did the trick!

    Paul Deutsch -

    Similar problem here. I was able to remove the PTFE tubing, but a thin column of PLA was left, sticking out about 15 mm (formerly inside the PTFE). The PTFE tube itself appears undamaged, other than slight scratching caused by pliers (gently applied while pressing the collet. I’ll examine it under a microscope before discarding it. Using a jeweler’s loupe, however, it appears the “upper” end of the PTFE tube would benefit from a wider “V” shape (flaring or funnel). I did not try that, as the printed piece it fits in would also need a wider “V”. This would help capture the tip of the filament as it is loading. The tubing is also slightly curved - gentle warmth helped to straighten it.

    To get the bit of PLA out, I used the trick above, setting the temperature to PLA (there is no menu entry for setting a specific temperature. I.e., the menu entries do not match the videos.) So I selected the lowest setting, allowed it to heat up a bit, and then gently pulled out the stuck PLA.

    John Drabik - Reply

    I believe that what caused this problem was a kink in the PLA when it was pushed into the spool for shipping. When I pulled the tip from the spool prior to the first loading attempt, I noticed a kink, almost a break, in the PLA. I (incorrectly) thought it would just melt as it entered the hot end, but after some filament had started to emerge during the first loading attempt, the PLA cracked and popped out of the top of the filament entry point. I then attempted to push more filament in behind it - it would have been better to stop and try to do a filament unload procedure instead. I suggest that, prior to first loading, that newbies (like me) be warned to cut 100 mm or so from the end of the PLA (i.e., to get past any kink or break) and then cut the a 45-60 degree angle.

    John Drabik - Reply

    Hello John,

    Sorry for the trouble you encountered, we will consider your idea.

    Martin L. - Official Prusa CS -

    My problem is different, the Prusa filament broke after two hours of printing and it continue to print another two hours till the print ends… the filament didn’t jump out of the detector so the print continues.

    Jen Ly - Reply

    Hello Jen, in that case you need to get it out manually and clean the hotend. If you need assistance, feel free to contact us on email info@prusa3d.com.

    Martin L. - Official Prusa CS -

    What does press the black collect mean? press it down? Squeeze it together? What is the bets way to do this? With fingers? With pliers?

    Jeffrey Henn - Reply

    So if the tube does not come out VERY easily when you press down on the black collet, you may have to heat up the hot-end. I did that and with a gentle press down on the collet, the tube slid out.

    Jeffrey Henn -

    Yes, by pressing we mean press the collet down towards the metal part to remove the tube.

    Martin L. - Official Prusa CS -

    I’ve had the same problem, but I’ve found is if you have the heatsink unscrewed, don’t try to pull it out, push it thru.. It slides right out or at least mine just did.

    Brad - Reply

  8. Now it is time to insert the new PTFE tube. Note, that each end of the tube is different. One end of the tube has "rounded" outer edge. This end must be inside the hotend.
    • Now it is time to insert the new PTFE tube. Note, that each end of the tube is different.

    • One end of the tube has "rounded" outer edge. This end must be inside the hotend.

    • Look at the other end, where the tube is drilled inside, the shape of the edge is "conical". This is the side, where filament enters the tube. This part must be outside the hotend.

    • Push the black collet in. Slide the tube all the way in and hold it!

    • Using the other hand pull the collet out and only then release the tube!!! THIS IS CRUCIAL for the hotend to work properly.

    • After you finish inserting the new PTFE tube, check all the parts are properly tightened and nothing got loose during the process.

    The last action in this step regarding the black collet is to pull it out. However, in the reassembly it looks like the collet is pushed back “in”. When should the collet be pushed back in? Unless I’m missing something, the steps are:

    1. push collet in

    2. insert tube

    3. pull collet out

    4. release the tube

    5. (apparently?) push collet back in???

    Can you pls confirm? Thanks!

    Todd Kanning - Reply

    Hi,

    The correct step - the last step to securely lock the PTFE tube is shown in the second figure. You have to push the PTFE tube all the way in - so that there is no gap inside the Hotend. Then push the PTFE tube inside while pulling the black collet up. By doing so, the PTFE tube is fixed and locked in place. It is therefore not meant to out the collet completely but only partially to fix the position of the PTFE tube. See the second figure.

    Martini H. - Official Prusa CS - Reply

  9. Place the hotend back inside the extruder. Ensure the orientation is the same as in the picture with cables on the left side. IT IS CRUCIAL to ensure the hotend fits to the extruder-body!!! The printed part is shaped according to the hotend. See the second and the third picture! IT IS CRUCIAL to ensure the hotend fits to the extruder-body!!! The printed part is shaped according to the hotend. See the second and the third picture!
    • Place the hotend back inside the extruder. Ensure the orientation is the same as in the picture with cables on the left side.

    • IT IS CRUCIAL to ensure the hotend fits to the extruder-body!!! The printed part is shaped according to the hotend. See the second and the third picture!

  10. Check once again the correct position of the hotend. Look from below the extruder. The heater block should be oriented, like in the picture. Take a look from the side of the extruder. The nozzle should be slightly below the printed fan-shroud.
    • Check once again the correct position of the hotend. Look from below the extruder. The heater block should be oriented, like in the picture.

    • Take a look from the side of the extruder. The nozzle should be slightly below the printed fan-shroud.

  11. Carefully and slowly push all the parts together. In case of any significant resistance STOP immediately and check, which part is blocking the movement .
    • Carefully and slowly push all the parts together. In case of any significant resistance STOP immediately and check, which part is blocking the movement .

  12. Tighten both screws, but ensure no cable is pinched on both sides of the extruder. Similar for the front side. Tighten both screws. Ensure no cable is pinched. Put back the M3x14 screw and tighten it.
    • Tighten both screws, but ensure no cable is pinched on both sides of the extruder.

    • Similar for the front side. Tighten both screws. Ensure no cable is pinched.

    • Put back the M3x14 screw and tighten it.

    • If you have removed the fan-shroud, put it back in. Then fix it in place with the M3x20 (M3x18) screw.

  13. Great job! You've just changed the PTFE tube in the extruder. Heat up the printer and try it out ;)
    • Great job! You've just changed the PTFE tube in the extruder.

    • Heat up the printer and try it out ;)

    If you review my earlier comment about the PTFE tubing needing a larger flare, after replacing the tube it is now just barely visible above the printed part, near the extrusion gears. This alarmed me a bit at first, since we were warned to be very careful that the new PTFE tube was well seated before raising the collet, so I pulled the tube out and re-seated it again, and re-pulled the collet. Same result, so I proceeded. Note that the PTFE was not visible inside the idler door before (as it came from the factory). But when I reloaded the filament, it went right into place with no problems. I was just able to perform the first printed calibration.

    John Drabik - Reply

Finish Line

23 other people completed this guide.

Jakub Dolezal

Member since: 02/20/2017

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6 Comments

Is there a guide like this for the MK3S?

Tim Graupmann - Reply

Hello Tim,

This is a guide for MK3S. For the MK3, it can be found here:

How to change a PTFE tube - MK3/MK2.5

Marcin M. - Official Prusa CS -

An excellent guide. Thank you for doing this. It was long overdue for the MK3S.

Doug Dobson - Reply

are the pre-cut / shaped PTFE tubes available for sale? I couldn’t find them in the shop

Derek Bosch - Reply

Hi Derek,

Yes, they are. You have to be logged in to be able to see them. If you have purchased your printer from a 3rd party, please contact us and we will enable access for your account.

Marcin M. - Official Prusa CS -

Wow really could use a good video about this as it must be a very common procedure, and i found the videos about other models VERY confusing. So many hack videos leading me down the wrong path. Once I found this everything was easy!

Jesse - Reply

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