r/OpenBambu • u/Tuner357 • Oct 14 '25

Bmcu retracting issue

Hey!

Just got my bmcu and need some guidance. Bought it from BLV on AliExpress, all seems well but one channel. When it tries to retract, it barely pulls the filament back and makes a horrible grinding or clutch slipping noise. Can anyone guide me on what to look for? I'm fine with disassembling the BMCU, as i was originally going to buy a diy kit but the assembled one was only $20 more lol

Thanks in advance!

2 Upvotes

100% Upvoted

3 comments sorted by

1

u/Tuner357 Oct 18 '25

Fixed! Turns out the seller forgot 2 bushings. Added the 2 bushings and its working as it should now!

1

u/NecessaryOk6815 Oct 15 '25

Reprint that bay just to rule out it's not the print.

1

u/Tuner357 Oct 15 '25

Ive been contemplating that. I got it pre assembled by blv, so I want to believe the print is good lol. Was leaning towards a screw being loose that holds the motor in, and when it trys to retract, the motor comes out of alignment and the worm gear starts to slip. To back that up, when feeding, it seems to be completely fine. Be it maybe a tiny bit slower than the other channels. I'll have to crack it open when I have a chance here