Before you proceed, let's make a fast disassembly and instal Y-motor-distance. Take a 1.5mm Allen key and release both screws on Y-axis endstop.
  • Before you proceed, let's make a fast disassembly and instal Y-motor-distance.

  • Take a 1.5mm Allen key and release both screws on Y-axis endstop.

  • Take a 2.5 mm Allen key and release both screws on Y-axis motor.

  • Keep in mind both endstop and motor are tied to the frame, proceed with caution or might break the cables.

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Use the motor to set proper distance for the Y-motor-distance. Place the motor next to the Y-motor printed part. Place the Y-motor-distance part at the other edge of the motor. The cut out part for the wiring must be upwards, see the picture.
  • Use the motor to set proper distance for the Y-motor-distance. Place the motor next to the Y-motor printed part.

  • Place the Y-motor-distance part at the other edge of the motor.

  • The cut out part for the wiring must be upwards, see the picture.

  • That's it! Now place the motor and the endstop back and tighten it. When ready, proceed to the next step.

I highlighted this problem when I first built my printer. The existing motor bracket is too flexible to keep the motor and end stop in the same position. This spacer is a good solution. Personally I printed a third party motor mount that had the spacer and more solidity built-in.

Jim Hatton - Reply

Hi Jim, thanks for the feedback. The spacer was added to the design to help with force redistribution. Which one, have you used?

Jakub Dolezal -

The marker (used in the next steps) is made as a countersunk hole, see the picture.
  • The marker (used in the next steps) is made as a countersunk hole, see the picture.

In earlier kits, like mine, this was just a dot of white paint.

Cristian Sandu - Reply

Hi Christian, thanks for the note. Earlier versions of the X-carriage had this countersunk hole filled with white colour.

Jakub Dolezal -

The Y-carriage of the MK1 has no mark. Thus those who upgraded from MK1 to MK2 might have marked themselves the Y-carriage. I have a barely visible mark in my case.

The asymmetrical aspect are the two middle holes that are not at same distance from their sides (one hole is closer to its side than the other by less than 1mm I think). This is very subtle.

See Step 7 and Step 8 of the “1. Y-carriage drilling” chapter in “Original Prusa i3 MK1 to MK2 upgrade” manual (that can be found in the “Prusa obsolete manuals” section) to figure the actual orientation in doubt. (There was a printed part to help identify it, but using a precise measure tool you can figure it too.)

Frederic Jolliton -

Nothing on my X-carriage. I’m glad I made a mark on the bottom of my carriage before unmounting. Just some professional habits. but i wonder why it can’t be upside down as it seems very symmetrical (rear/front).

Ron - Reply

Hi Ron, as to my knowledge there was no change of design and the Y-carriage should be marked. As it is NOT SYMMETRIC part due to structural reason and if you turn it wrong face up, you won't have aligned holes in the carriage and in the heatbed.

Jakub Dolezal -

When placing bearings onto the Y-carriage, make sure that they are oriented as shown in the picture. One of the tracks has to be in line with the cutout for the bearing!
  • When placing bearings onto the Y-carriage, make sure that they are oriented as shown in the picture. One of the tracks has to be in line with the cutout for the bearing!

  • This orientation has to be followed in all 3 bearings on the Y-carriage!

  • Marker on the Y-carriage must be facing the table (not visible)!

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Begin by locating the marker, at this step the marker should be facing the table (not visible) and only then you can add the bearings. If you place bearings to the same side as marker, you will have issues later! Insert a 3x20x16 u-shaped bolt into the Y-carriage as shown on the picture. Place the linear bearings in cutouts.
  • Begin by locating the marker, at this step the marker should be facing the table (not visible) and only then you can add the bearings. If you place bearings to the same side as marker, you will have issues later!

  • Insert a 3x20x16 u-shaped bolt into the Y-carriage as shown on the picture.

  • Place the linear bearings in cutouts.

  • On the side with two bearings, slide the bearings to the center, towards each other as close as possible.

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Use pliers to tighten the u-shaped bolts. Step 1: place the nuts on the u-shaped bolt and insert a bearing. Step 2: using pliers tighten the nuts until you reach the surface of the Y-carriage, then stop tightening!
  • Use pliers to tighten the u-shaped bolts.

  • Step 1: place the nuts on the u-shaped bolt and insert a bearing.

  • Step 2: using pliers tighten the nuts until you reach the surface of the Y-carriage, then stop tightening!

  • Step 3: use pliers again and rotate with the nuts only 1/4 of circle to finish the tightening.

  • Don't tighten the nuts more than is described above, or you will deform the bearings!

5.5 mm wrench if you're wondering.

Dave Cook - Reply

Hi Dave, thanks for the comment.

Jakub Dolezal -

Use the mid-sized smooth rods (330 mm)
  • Use the mid-sized smooth rods (330 mm)

  • Insert the 8mm smooth rods into the linear bearings on the Y-carriage.

  • Be very careful! Insert the rod straight into the bearings, do not apply too much force and do not tilt the rod!

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Insert the assembled Y-carriage into the Y-axis stage. Ensure the correct orientation of parts, single bearing on the side of the Y-axis motor.
  • Insert the assembled Y-carriage into the Y-axis stage.

  • Ensure the correct orientation of parts, single bearing on the side of the Y-axis motor.

  • Note the location of the Y-carriage orientation marker - it's important the Y-carriage is oriented as in the picture!

  • Insert zip ties into the holes in Y-corners and tighten them using pliers.

  • Ensure the correct orientation of zipties (head of the ziptie should be facing out from the Y-axis stage).

  • Press smooth rods (330 mm) all the way in the Y-corners holders. Don't use excessive force.

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Rotate the printer onto the PSU side.
  • Rotate the printer onto the PSU side.

  • Move the Y-belt-holder below the Y-carriage and locate the holes. Insert screws from the holder through the carriage.

  • To hold screws temporarily in place, you can use M3n nuts. We will remind you to remove them just before the heatbed assembly.

I needed nuts to secure the belt holder. I don't recall removing them.

Bill Waggoner - Reply

Hi Bill, thanks for noticing. I've updated the manual with a note.

Jakub Dolezal -

You can't tighten the belt holder here. It screws into the print bed. The title is just misleading.

Dave Cook - Reply

Hi Dave, I've added info regarding the M3n nuts. Now the tightening is possible.

Jakub Dolezal -

Don't mix old and new smooth rods and bearings. For the printer's best performance you need to use those in the upgrade kit. LM8UU linear bearings (new) 8mm longest smooth rods (new)
  • Don't mix old and new smooth rods and bearings. For the printer's best performance you need to use those in the upgrade kit.

  • LM8UU linear bearings (new)

  • 8mm longest smooth rods (new)

  • Carefully slide linear bearings on rods.

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Insert new LM8UU linear bearings into the printed parts (X-end-motor and X-end-idler) as shown in the pictures. The bearings should be in line with the X-ends as highlighted in the picture. You can press on the flat surface for easier insertion.
  • Insert new LM8UU linear bearings into the printed parts (X-end-motor and X-end-idler) as shown in the pictures.

  • The bearings should be in line with the X-ends as highlighted in the picture.

  • You can press on the flat surface for easier insertion.

  • Place two bearings in a way that the inner balls of the second bearing are rotated 45° compared to the first. This way you will achieve greater contact with the smooth rod. See third picture for more details.

  • Note these pictures are illustrative to highlight proper assembly of the bearings. You might have motor and endstop already attached.

Aren’t these the Z axis parts ?

Jim Hatton - Reply

Hi Jim, those printed parts belong to the X-axis and in the same time are used to move along Z-axis.

Jakub Dolezal -

Don't use X-carriage from your disassembled printer, use the new version you've printed. Insert zip ties into the X-carriage as shown in the picture.
  • Don't use X-carriage from your disassembled printer, use the new version you've printed.

  • Insert zip ties into the X-carriage as shown in the picture.

  • Ensure the correct orientation of zip ties.

  • Note your printed part might look slightly different, but the procedure is the same.

Are there Gcode files for this assembly ?

Dave Cook - Reply

Hi, Dave, the new X-carriage is part MK2S upgrade pack. You can download the g-code here: http://www.prusa3d.com/prusa-i3-printabl...

Jakub Dolezal -

Ive just gone straight ahead and disassembled everything to discover the 'new' bits are not in my upgrade pack ! What now ?

Graham Bayley - Reply

Hi Graham, what do you mean by the new bits? New printed parts? There is a remark about downloading and printing right in the beginning of this manual.

Jakub Dolezal -

I have the same thing.. it wasn’t explicit enough in the manual.. it was easy to read over that and since I said “printed parts black” i just assumed it was in there

Pieterjan Ruysch -

Insert new rods with new bearings fully into the printed parts. Ensure the correct orientation of the parts and rods (rod with 2 bearings must be on the side with the nut trap).
  • Insert new rods with new bearings fully into the printed parts.

  • Ensure the correct orientation of the parts and rods (rod with 2 bearings must be on the side with the nut trap).

  • Insert the rods very carefully. Do not tilt the rods too much.

  • Note these pictures are illustrative to highlight proper assembly of the rods. You might have motor and endstop already attached.

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Place the X-carriage on the X-axis base as shown in the picture.
  • Place the X-carriage on the X-axis base as shown in the picture.

  • Ensure the correct orientation of the X-carriage.

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Use pliers to tighten the zip ties. Make sure that bearings are in the position as shown in the picture (a bearing should be fully seated and bottomed out in the carriage). Use pliers to cut off any excess zip tie.
  • Use pliers to tighten the zip ties.

  • Make sure that bearings are in the position as shown in the picture (a bearing should be fully seated and bottomed out in the carriage).

  • Use pliers to cut off any excess zip tie.

  • Move the zip tie head to the position as shown in the last picture.

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Insert M3 nuts (4 pcs  total) in the printed parts as shown in the picture. Insert M3 nuts (4 pcs  total) in the printed parts as shown in the picture.
  • Insert M3 nuts (4 pcs total) in the printed parts as shown in the picture.

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Use M3x12 screws (4 pcs) to tighten nuts in place. Use 2.5mm Allen key to tighten the screws.
  • Use M3x12 screws (4 pcs) to tighten nuts in place.

  • Use 2.5mm Allen key to tighten the screws.

  • Make sure the nut is oriented just like the picture!

Add Comment

In the following steps, use the shortest rods (320 mm).
  • In the following steps, use the shortest rods (320 mm).

  • Don't mix old and new smooth rods. For the printer's best performance you need to use those in upgrade kit.

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Ensure again you are using the new smooth rods! Insert Z-rods (the shortest ones) inside the Z-axis-bottom parts.
  • Ensure again you are using the new smooth rods!

  • Insert Z-rods (the shortest ones) inside the Z-axis-bottom parts.

  • Note this step is illustrative, the motor cables should be already tied to the frame.

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Carefully slide the X-axis on rods and trapezoid screws. By rotating both screws simultaneously let the X-axis to slide until both trapezoid screws are exposed as in the picture. Insert the X-axis very carefully, perfectly in axis with the bearings and with a minimal force. Insert the X-axis very carefully, perfectly in axis with the bearings and with a minimal force.
  • Carefully slide the X-axis on rods and trapezoid screws. By rotating both screws simultaneously let the X-axis to slide until both trapezoid screws are exposed as in the picture.

  • Insert the X-axis very carefully, perfectly in axis with the bearings and with a minimal force.

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Place parts on the frame as in the picture. Use 2.5mm Allen key to tighten the parts to the frame. Check both leadscrews in the upper part of printer, they shouldn't touch the edges of the printed part. If so, release the motor holder at the bottom and slightly move it.
  • Place parts on the frame as in the picture.

  • Use 2.5mm Allen key to tighten the parts to the frame.

  • Check both leadscrews in the upper part of printer, they shouldn't touch the edges of the printed part. If so, release the motor holder at the bottom and slightly move it.

  • All screws in this step are M3x10 (4 pcs).

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Insert the flat part of the X-GT2 belt (longer one) into the X-carriage as in the picture. A reference video is included at step 28 covering steps 20-27.
  • Insert the flat part of the X-GT2 belt (longer one) into the X-carriage as in the picture.

  • A reference video is included at step 28 covering steps 20-27.

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Guide the belt around the pin as shown in the picture. Insert the belt all the way into the belt holder as shown in the picture.
  • Guide the belt around the pin as shown in the picture.

  • Insert the belt all the way into the belt holder as shown in the picture.

  • Note that there is no belt going out of the X-carriage, it's IMPORTANT.

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

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Guide the X-axis belt through the X-carriage.
  • Guide the X-axis belt through the X-carriage.

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

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Use pliers to tighten up the X-axis belt.
  • Use pliers to tighten up the X-axis belt.

  • Insert the flat part of belt as shown in the picture.

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Guide the belt around the pin as shown in the picture. Push the belt all the way into the X-carriage.
  • Guide the belt around the pin as shown in the picture.

  • Push the belt all the way into the X-carriage.

  • The belt shouldn't be tight at the moment.

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Rotate the motor back
  • Rotate the motor back

  • Screw in the removed M3x18 screws.

  • If you have to apply too much force and are experiencing troubles, rotate the motor back, repeat previous step while making the belt more loose.

  • The belt should be quite tight (see the video at step 28).

  • This step is illustrative, you don't need to remove the frame.

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  • Insert the flat part of X-GT2 belt (longer one) into the X-carriage, around the pin. Guide the X-axis belt through X-end-idler, around the 623h bearing with the housing and back. Guide the X-axis belt through the X-carriage. Guide the X-axis belt through the X-end-motor, around GT2-16 pulley and back.

  • Remove the two M3x18 screws. Rotate the motor counter-clockwise.

  • Insert the flat part of the belt around the pin.

  • Rotate the motor back. Screw in the removed M3x18 screws.

  • Video is available in an online (digital) version only.

  • All done! You can continue to the next chapter - 3. Extruder Assembly

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Finish Line

36 other people completed this guide.

Jakub Dolezal

Member since: 02/20/2017

81,744 Reputation

134 Guides authored

10 Comments

Actually you have also to release the belt from Y-belt-holder and remove the Y motor to be able to insert the Y-motor-distance.

Kolouš - Reply

It is enough to release the motor with the belt still on, see the updated instructions.

Jakub Dolezal -

In fact, there are no instructions here about the Y-distance part at all. This needs some of the text from the MK2S Kit Y-axis assembly manual.

Christopher Day - Reply

Hi Christopher, instructions added for placement of Y-distance.

Jakub Dolezal -

Does Z axis have an end stop? I get an error that say end stop error for wiring on z axis. Was there suppose to be an end stop for Z axis

Lee Garza - Reply

Hi Lee,

Z axis is on the top limited by the printed Z-axis-top-left and Z-axis-top-right parts. The other side is controlled by P.I.N.D.A. probe. If you have wiring issue please ensure the cable from P.I.N.D.A. probe is connected properly and not pinched, also try to do the Z calibration again.

Jakub Dolezal -

No Y distance part included in my kit (that I can find anyway). How critical is this and how do I get one?

Michael Roznovsky - Reply

Hi Michael, you can assemble the printer without it, but I recommend to download STL file from our site and print it. It helps the motor to spread the load from heatbed movement to the Y-axis frame. STLs are here: http://www.prusa3d.com/prusa-i3-printabl...

Jakub Dolezal -

I’m in a bit of a fix. I printed the required parts and disassembled my machine and began the reassembly process. I got to the point where the zip-ties are to be reinserted. I then discovered that the x-carriage channels for the zip-ties did not go through so the zip-ties could not be fully inserted. Any ideas how I can clear out these semi-circular channels?

David Lockwood - Reply

I didn’t have the Y distance part in my MK2S upgrade kit either.

Pieterjan Ruysch - Reply

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