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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 -

    Hi, I got stuck on this point. The problem is that I can not unscrew the left screw marked by green. The problem is most likely loosen nut on the other side. I mean it does not hold its position in the plastic part. When trying to unscrew, the screw does not go out, intsted it is just clicking on the same place. I am afraid I’ll have to get to it and disassemble much more parts. Do you have any trick for this situation? Thank you.

    Lukas Palkovic - Reply

    Hi Lukas, unfortunately you might have to remove the extruder assembly from the X carriage to see what exactly is wrong.

    Filip M - Official Prusa CS -

    The “green” screws, what size are they? No where does it say the length.

    johnwinegard@gmail.com - Reply

  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)

    You so often use the word “prepare” when in fact it doesn’t call for any actual preparation. Preparation means (in English) that you’re going to DO something to it. But way too often in these instructions it merely means to GET the part so you have it available for some subsequent instruction.Also, in THIS particular photo you’ve circled one end of the tube, but there’s no indication of what it is you’re trying to point out. The PTFE tube that I have (came as an extra with the kit) has one end that is slightly tapered. Is THAT what you’re trying to point out? And if so, WHY?

    Roger Garrett - Reply

  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

    What can I do if the black ring broke ? It was impossible to get it down..

    Thanks

    Stanladriere - Reply

    Hello there,

    Please consult us via online chat, this part is not available in the online store but we can still help you with this.

    Martin L. - Official Prusa CS -

  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

    Alright, I give up at this point. I have had to exchange the PTFE tube for 4-5 times now within the first week of my new printer. Every time now I get the characteristic “glans”-style head at the bottom of the PLA that I pull/force out of the obstructed PTFE tube. This happens every time after just a few hours of printing.

    I understand that this is caused by a gap between the PTFE tube and the end of the hotend where the nozzle section is supposed to fit snug to it inside the heatbreak by doing this very step here correctly: I push down the PTFE tube as fast as I can by now, while having the black ring pushed down as well, I keep pushing hard as f on the PTFE tube while then pulling the black ring out with my other hand.

    What am I doing wrong here?

    BTW: I have done successful cold pulls in between as well now, so there is no obstruction in the nozzle. I have stopped doing that now though, as I think the cold pull might be causing the gap as well.

    Patrick Bauer - Reply

    Hi there, that doesn’t sound like it’s related to the tube in this case.

    In case you’ve taken the hotend apart, you might want to double check the assembly with the E3D official manual:

    https://e3d-online.dozuki.com/Guide/V6+A...

    Perhaps something wasn’t re-assembled properly near the heaterblock, and that magnifies the heatcreep.

    Filip M - Official Prusa CS -

    Still keeps happening every 2-8 print hours max. I meant to say I push “hard” down on the PTFE tube while pulling the black ring back, not “fast” of course. Help appreciated!

    Patrick Bauer - Reply

    So for others coming here with the same problem and since the Prusa support seems to ignore it (not the best first impression so far, despite the sympathetic videos of Joseph Prusa and the overall great impression of the company), here is what looks like a solution:

    1. The problem seems to be one of the big (if not the only) obvious design flaws still present and discussed widely, without so far being acknowledged by Prusa, see here for example: https://forum.prusaprinters.org/forum/or... with great video that shows the problem cause very well.

    2. The reason seems to be that Prusa leaves off a ~1 cent plastic ring at the moment (MK3S), usually provided with E3D V6 hotends.

    3. The solution is super simple. Print or order a 10 cent plastic ring to install around the black ring: https://www.thingiverse.com/thing:349996... or https://e3d-online.com/collet-clips-pack...

    Patrick Bauer - Reply

    Hello Patrick, collet ring is not necessary if your black collet works as it should.

    If your collet is unable to properly hold the tube and lets it go over time, then please contact our support to receive a replacement (you can use email - info@prusa3d.com or livechat - shop.prusa3d.com/).

    Filip M - Official Prusa CS -

    Well, so far with the collet ring installed, the printer has been running for a few days without any issues so that did fix it. I find the explanation provided in the video that I linked (within the prusa forums post discussing this topic in length) very convincing that this issue can very well arise even with a working collet. That must be the reason that they are usually provided and that so many people install them to fix this issue (just look at the forums).

    I am happy with my working setup now. It’s just a bit weird that Prusa seems to have such a hard time acknowledging this design flaw (not only here), given the stellar reputation that you (rightfully) earned and that it could so easily be fixed by just providing a printed 1 cent piece.

    Patrick Bauer - 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!

    So judging by that the orange bullet pic, we’re supposed to take the external panel off, then align it to the hotend? It’s not clear what the user is supposed to do to align it to the extruder body. The pic shows it completely off. I didn’t take it off, but the screws released from the cover, which made it difficult to realign things. A better way to do this would be to align the extruder in the correct orientation on the immovable piece that is left on the rods. Since that is stationery (and not unscrewed) its much easier to sit the metal piece within that, then point it parallel to the print bed.

    The hardest part is re-assembling it. One thing not noted here is if you accidentally unscrew your screws completely, it is difficult to align the large, barely visible pin on the floating piece that holds the two pieces together. If you don’t have that aligned, it’ll never screw back on properly. I eventually got it back on, but it still didn’t work (clicks when i try to load PLA now). Big pain.

    Arezendes - Reply

    Hello Arezendes,

    in this case, you don’t need to take off anything. just get the front parts with the motor fan enough from the parts that hold on the rods. it’s true that it takes a little bit of practicing. what you describe as a better way is what you’re supposed to do, the middle photo is there just to show you which part should be aligned to which groove.

    Martin L. - Official Prusa CS -

    Hello, it’s not necessary to remove the panel completely - it’s just a reference picture to show you how the hotend should fit.

    Filip M - Official Prusa CS -

    Should the hotend engage something that holds in in place? When I push it into what looks like the right position, it drops when I stop holding it in place.

    Sam Brenneman - Reply

    Hi Sam, the front extruder part should hold it in place.

    Filip M - Official Prusa CS -

    Okay, yes it does hold it in place, but I am having trouble seating it into the right place. It isn’t going in as far as it should by your pictures, and I can’t feel anything with which to engage it. The nozzle is much lower than the PINDA, much lower than it should be. I can’t see anything without disassembling further, and I have no build guide or exploded drawing to help me figure out what I’m doing, as this machine came pre-built. I have loosened everything again, but no luck. Should I be pushing it into place at an angle? I’ve put a couple of hours into this so far.

    Sam Brenneman - Reply

    I confirmed the critical step of pushing the hotend upward enough during reassembly by removing the extruder idler spring and opening the idler door so I could see inside. If the hotend is seated properly you should see the tip of the PTFE tube just below the extruder gear. It’s easy to see, white on black. It’s a bit tricky and I needed to loosen the four screws a bit more to get the proper gap into which the hotend fits.

    Lane Hauck - Reply

  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.

    Unfortunately one of the captive nuts is spinning so I am not sure how I am going to be able to take the head apart again the next time it happens. I expect it will just be more involved possibly needing me to replace part of the carriage or possibly epoxy the nut in place. So be careful about over tightening - I wasn’t !

    trevor clapp - Reply

  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

    This should be included in the MK3S to MMU2S upgrade guide. If i would have known that this step is crucial for successful filament changes, it would have saved me 10 hours lifetime i spent for searching the cause.

    Andreas - Reply

    Hello Andreas!

    Can you be more specific? Which part of the guide are you referring to?

    Martin L. - Official Prusa CS -

    After this you need to recalibrate Z and first layer for sure…

    Peter Jankovsky - Reply

Finish Line

38 other people completed this guide.

Jakub Dolezal

Member since: 02/20/2017

232 Guides authored

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12 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

Hello. Is there a guide like this for the MK2S?

guillaume - Reply

Hi, unfortunately not. The whole process is similar, though, so you can supplement it with this guide.

Filip M - Official Prusa CS -

And where is the guide for the older MK2, please?

Egil Kvaleberg - Reply

Hello Egil,

We do not have one, unfortunately. The hotends are physically the same in both MK2/S and 3/S. As for the PTFE itself, you can also see video instruction here: https://youtu.be/jmmfh2An5Mc?t=150

Marcin M. - Official Prusa CS -

Thank you for the guide - and the very helpful comments! I had an issue or two along the way but with the previous experiences of others and the helpful comments, I was fixed in no time - thank you!

mel_o - Reply

i somehow got PLA stuck in the PTFE and couldn’t load more. this was the fix for me. Thank you for the guide it was perfect.

Darius - Reply

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