MBG36F hub is making a nasty grinding sound

[Stockholm Pete]

My (newish) MBG36F hub is making a nasty grinding sound which upon removal of the aluminium cover looks like it could be the magnets rubbing on the hub casing. Is this likely or has anyone else experienced this problem. The problem gets worse with load - from no sound at low load and steadily making a louder grinding sound as max load is reached. Pleasehelp me fix this as I am now addicted to this machine for my commute!

[Bikemad]

Hi andto the forum Pete.

I seem to recall another member (DirtyGinge) having noise problems with a similar motor because the countersunk bolts that held the cover on were too long and would not tighten properly.
I think he ended up cutting a small section of thread off the end of each bolt so they could be tightened correctly.

I suggest you closely inspect your cover to see if there is any sign of movement which might be causing the noise you are hearing.

Alan
 

[Stockholm Pete]

Thanks for the advice Alan but that is not the problem. Upon inspection the bolts are the correct length and do not interfere with any moving parts. The grinding sound comes from within the hub somewhere. Has anyone had problems with the magnet flywheel/winding assembly on the spindle that can be taken out of the hub? Are there bearings (not the wheel bearings) in there? Where can I get a drawing of what is in there?

[e-lmer]

Is there any side to side play in the wheel? 
It may be that a spacer is incorrect or missing
and the wheel is torquing sideways.

Also, I think that someone years ago was complaining
that his speed controller was loose inside the hub,
which rubbed until it jammed and seized the wheel.

I don't know if that was true, but I do remember hearing it.

[Stockholm Pete]

Thank you for your comments.
Does anyone have a drawing or photo of the parts inside the hub so that I can acertain if everything is there, including spacing washers? Where is the speed controller and what does it look like?
There is no play in the wheel there may be some play internally allowing movement under drive force. Are there any spacing washers inside the hub?
Peter

[e-lmer]

I had not looked at the drawing, it appears
this is a geared motor.

This may be an issue with the internal gearing.

Is it new enough to be under warranty?

[Bedmountain]

Hi andto the forum Pete.

I seem to recall another member (DirtyGinge) having noise problems with a similar motor because the countersunk bolts that held the cover on were too long and would not tighten properly.
I think he ended up cutting a small section of thread off the end of each bolt so they could be tightened correctly.

I suggest you closely inspect your cover to see if there is any sign of movement which might be causing the noise you are hearing.

Alan
 

I've just opened up my MP3, not because of a grinding sound, but because the controller has blown.

On opening the cover I can see the plate underneath has been badly grooved by the ends of the countersunk screws in the cover plate (see pic).

I never heard a grinding noise but it can't have been adding much to the performance of the motor!

This must be an issue with all these MP3's? Unless I just happened to get one with extra long screws?

[edit] ignore me! As Bikemad has pointed out it is the disc brake mounting screws that I fitted that have caused this scoring....

[Stockholm Pete]

Thanks for trying to help anyway.