Clear all

Bondtech Gears Issue - Help Please  

New Member
Bondtech Gears Issue - Help Please

Hi Guys,

I have a i3MK3s+ that is about 2.5 years old.  I do a lot of printing, about 10 hours a week on average.

Today, I noticed when I changed a roll of filament, as the filament went in, there was a clicking sound (about 1 click every other second) and the filament was not being pulled in as is normal.

When I tried to print, very little filament was coming out.

I checked the tightness of long screw with the idler spring.  It seems to be adjusted right according to the spec in the manual.

I opened the Idler Door and made sure the bondtech gears were lined up with the Hotend PTFE Tube and not loose, they were.

After all this and trying to loosen or tighten the tension Screw with the idler spring, no luck.  It's still making a clicking sound every couple of seconds and it is not pulling the filament in.  (Not pulling it in as it normally does when loading filament.)

Do bondtech gears wear out?

Could the bearing be shot?

Could it be anything I'm missing?

Thanks for the help.




Posted : 01/08/2022 12:13 am
Veteran Member Moderator
RE: Bondtech Gears Issue - Help Please

Hi Tejay, 
the Bondtech  idler bearing shaft is a bit short, can you check that that the idler bearing shaft is located so that it is supported by both bosses in the door part? if one end slips out of the supporting boss, the idler will cease to run parallel to the motor shaft. 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 01/08/2022 8:29 am
Famed Member

While you're in there check you have not chewed up the end of the PTFE tube and then if all seems ok heat the hot end and manully push some filament through - and finish with a cold pull.

Do bondtech gears wear out?

Could the bearing be shot?

Anything is possible but 'a lot of printing' starts about the 20 hours a day level and with regular maintenance Bondtechs and bearings will last much longer than yours.


Posted : 01/08/2022 9:20 am
Honorable Member
RE: Bondtech Gears Issue - Help Please

Check that the idler gear on the door spins freely. This can get jammed up with bits of filament, dust, and crud that prevents it turning freely.

If it’s stuck it will cause the symptoms you describe. Start by removing the idler door. You’ll have to carefully tap the axle out so you can properly clean it and the bearings. Be sure to support the far side ‘ear’ so you don’t break it off while tapping out the axle.

Clean the parts with IPA and dry thoroughly. You can put a tiny drop of sewing machine oil on the bearings but be sure to wipe off any excess before reassembly.

See Steps 32-36 here:


Posted : 02/08/2022 3:56 am
Active Member
RE: Bondtech Gears Issue - Help Please

Could be the filament. I dry any open plastic before I use it. I also keep filament in a bag in their box 4 in a tub with two Wisedry 50 bags. I have two SUNLU dryers  just set temp to match plastic and it runs the time  PLA and TPU 40c ASA50c

I print Asa from a dry box and TPU from a heater. 

I would pull out your gears clean them and replace your tube. Wet plastic any type can cause this grinding and fills gears. The fans in a non covered machine import every piece of dust they can find and cause over heating. It likely just needs a cleaning. The advantage of building your own it you pretty much already know the wear or dirt collectors. 

 one on my list is crap filament. Prusa ASA kinda blows me away and I think 99% of its superior work is that fine [email protected] 

if you keep the head clean should last years. If you replace it with a Bondtech you have to keep it clean. 

I know it’s a pain to tear down but worth it just take your time. 

Be brand new used in an hour 

Posted : 03/08/2022 8:47 pm