BLDC Hub Disassembly

[mikew8760]

I have a rear wheel which I wish to dismantle in order to examine the internals of the motor. However, not being conversant with the construction of the hub I'm at a loss to know how it comes apart. I've attached a couple of photos of each side of the hub. I have already deduced that I will need a splined tool to remove the freewheel, but it's not clear to me that this will allow access to the motor. I have seen on Youtube the use of a hub-puller to extract the spindle from a bearing and wonder if this is necessary?
Any advice much welcomed.

 

[Woosh]

the only specific tool you need is a freewheel removal tool.
after you remove the freewheel, the rest comes out quite easily.

 

[mikew8760]

Thanks for your response. That sounds promising; of course the next problem I discover is to identify exactly which tool will fit!! The only clue is the name EPOCH on the freewheel. It's a 12 spline profile, and I imagine the same as Shimano or somesuch. I've looked on-line for profile dimensions without luck.
Again, any suggestions welcome.

 

[Nealh]

It looks fairly easy once the freewheel is off.
Just undo the six face plate screws and possibly any axle retaining nut that may be behind the freewheel, then gently pry/lift off the face plate. Two flat wideish levers opposite each other and apply equal pressure moving around the hub if necessary.
Sow us another pic when freewheel is removed.

 

[Woosh]

Thanks for your response. That sounds promising; of course the next problem I discover is to identify exactly which tool will fit!! The only clue is the name EPOCH on the freewheel. It's a 12 spline profile, and I imagine the same as Shimano or somesuch. I've looked on-line for profile dimensions without luck.
Again, any suggestions welcome.

Get something like this, it's a set of two with different spline width.

https://www.amazon.co.uk/Cassette-Freewheel-Lockring-Remover-Spanner/dp/B01MQE2TZC/ref=sr_1_6

 

[mikew8760]

Many thanks for everyone's help - I'm OK with the electrics but rather rusty (pun?) on the mechanicals. The photo shows how far I've got, but it looks as though I now need a hub-puller to extract the shaft from the remaining bearing? I've given it a gentle tap with a rubber mallet, but nothing moves.
If it is removed with a puller I'm then concerned how it might be pushed back in? Any suggestions welcome.

 

[Woosh]

the motor core is held by magnetic force - you only need a good bench vice to hold the motor core by its spindle, then push the shell off with brute force.
As soon as the core moves, the magnetic force breaks so be careful.

 

[mikew8760]

Thanks Woosh for the advice, and I was expecting the same. But I've tried applying a force by carefully standing on the rim, that's about 100kg, and nothing budges! I suspect the inner race of the bearing has rusted onto the shaft, and more force is needed to break the joint. A hub puller is, of course, another tool I don't have, so any bright ideas welcome!

 

[Woosh]

Clamp the motor spindle as shown, remove all nuts, clips, washers from the top above the ballbearing, then pull up the shell.
The outside of the top ballbearing may get a bit stuck to the motor shell.
Rocking the shell from side to side a little at the beginning may help.

 

[mikew8760]

Thanks for all your help. Had another go at it today; I had expected there to be a fairly heft magnetic detent, but in this case there is none. A squirt of WD40, a little heat from a mini blow-torch and a bigger hammer freed the shaft from the bearing. I now have the stator and rotor magnets free of the hub, like your photo. I can see it will be another challenge to remove the rotor ring and gears to access the rear of the rotor, which is where the 3 Hall sensors ( I think are faulty) are lurking.There is one Hall sensor activated by a tiny magnet in the hub which I presume is for wheel speed.

 

[Woosh]

There is one Hall sensor activated by a tiny magnet in the hub which I presume is for wheel speed.

that's correct.
The 3 hall sensors are soldered to the same board. Make sure you note down the orientation of the sensor.
Best to test them and take a picture before desolder them.
Usually only one dead sensor is enough to cause the motor to misbehave.