Prusa Research MMU3 Manual Del Usuario página 104

PASO 31 Extruder fasteners parts preparation
PASO 32 Extruder reassembly
Fully tighten the two M3x40 bolts at the front of the extruder.
Add the fan to the extruder and push it to the back. There are cables behind the fan.
You can GENTLY push the cables into the dedicated channel using an Allen key.
Before you proceed to attach the fan, make sure all the cables are inside the
channel.
The fan has two sides, one has a sticker with markings on it. Make sure, this
side is facing to the inside of the extruder.
Fix the fan using the following screws (depending on the fan version):
M3x14 / M3x16b screw (3x)
M3x20 / M3x22b screw (1x) in the bottom corner.
104
9B. Mod extrusor MK3S+ (KIT)
Ensamblaje Original Prusa MMU3
Para los siguientes pasos, por
favor prepara:
M3x40 screw with spring (1x)
(Extruder Idler tension screw. Might
be still in the extruder.)
M3x40 screw (2x)
M3x20 screw (1x) (Extruder fan
bottom corner)
M3x14 screw (3x) (Extruder fan)
There were two versions of the
Extruder fan supplied. Most
printers have Noctua fan, but if
you have Delta fan, there are
slightly different M3x16b and
M3x22b screws. Use the screws
you removed from the fan
earlier.
M3x10 screw (4x) (x-carriage-back)