Motor difficulties, Shaft Comes Loose with Red Threadlocker!

I’ve seen a similar thread but I’m not sure as whether the issue was fixed.

My Motor Can, after rides, loosens from the shaft allowing for slight rotation between the motor can and the motor shaft. The two setscrews on the NON pulley side come loose. I have tightened them with red threadlocker and still, they come out!

Torqueboards 6355 190kv

I have a bluetooth chip attached and my live current readings never exceed 20-30A on a 6S setup temps never go above ~50C which from my understanding is much below what red is rated to handle (450 Faren)

I do a lot of neighborhood riding and I guess the tar segments in the roads just are too much for the set screws to handle? From what I am told the shaft is flat spotted where the set screws attached or I would lose all torque when they come loose slightly.

I let it cure for 24 hours each test and usually I can get 3-4 miles before checking and noticing slop.

I hope I’m doing something wrong here… any suggestions?

Maybe try sanding down a flat spot on the motor shaft to screw in keyways? Red threadlocker has never failed me to this day…

I’m sorry I don’t fully follow. Are you suggesting put a key between the motor can and the shaft?

Yeah exactly

Are you allowing your thread locker the full 24hr to cure?

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Instead of red loctite use the green 68020180802_133424

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I’m not sure this is possible/I don’t possess the means to perform this, but thank you for the suggestion!

Yes a full 24 Hours, if not longer

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I think I’ll be trying this soon, I’ll report back. The use case for that seems to be close to what I’m looking for, we’ll have to see if it holds up. Also, thanks for the suggestion!

Take out both set screws and put in a few drops of Loctite 680 or 648. Turn the can around the shaft a few times then align the holes with the flat spots that are probably already there on the shaft. Make sure the can is all the way on the shaft by pushing the shaft against the can, maybe even tap it slightly with a small mallet. Let the loctite cure a few hours then put in the set screws using blue or red loctite. I had the exact same problem on one of my motors and this fixed it.

Great point, will make sure to include the green between the can/shaft connection!

I would avoid using green loctite on the set screws as it will make them impossible to remove in the future and heating the can with a blowtorch to do so is not a good idea. Use it only on the can-shaft interface.

Keep in mind, I’ve already used red on the setscrews and they come off like butter it. Is green that much more powerful?

They’re both very powerful adhesives, but 680 is designed specifically for this purpose.

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I don’t mess with set screws for the motor pulley. It lead to way more hassle then I was willing to handle. Add a little 680, then do like the Ronco’s infomercial, set it and forget it! But seriously, definitely let it cure for that 24hrs. Ever since @Eboosted had the post with the blowtorch to remove in 30 secs, I haven’t used a set screw on any motor pulley.


They come off like butter because they are the ones holding the shaft in place and the load from the shaft slowly works them loose. After you use green loctite all they will do is fill the thread holes. Keep in mind this is the can we are talking about not the pulley. Heating the can to more than 250C to break the green loctite can permanently damage the magnets. This is not a problem since I see no reason to disassemble the shaft.

It is the setscrews between the motor can and the shaft these set screws are NOT the motor pulley ones.

Great news! I loosed them half way and in doing so the loctite cured again with the set screws not attached to the shaft. I managed to get one out, the other i have stripped. It was loose enough to back the shaft out and I had to file the bit of that shaft preventing me from sliding the shaft out. I now have the shaft out and I will see about: A, getting the set screw out. B putting the shaft in an sk3 motor I have.

My fault, that’s what happens when you attempt to read posts at 1am. With that said, I use blue and never had issues with my TB 6374 or the 50mm motors. Even with the crap roads I do hit on occassion… Had way more issues with set screws on my mounts then my motor can.