Bafang 8FUN QSWXK motor leaking oil.

[chain]

Here we have a Bafang 8FUN QSWXK motor leaking oil on one side only.

http://www.coolmainpress.com/miscimage/pedelec/bafang_8fun_qwsxk_leaking_grease.jpg

What do you reckon? Should I panic? Rebuild it -- the dedicated tool is pretty expensive? Ignore it? Order a new motor or wheel to keep on standby?

All input welcome.

Andre Jute

 

[wurly]

Andre
I don't think it is oil. It looks like aluminium rubbing together and what you see is the deposits being washed out. Does it make a noise? is there grit between the casing or is the cover loose?

 

[chain]

Andre
I don't think it is oil. It looks like aluminium rubbing together and what you see is the deposits being washed out. Does it make a noise? is there grit between the casing or is the cover loose?

The black stuff feels slightly gritty. The cover doesn't appear to be loose. We've had a few warmish days, on which I took longer hilly rides than normal, but the motor has never been even lukewarm.

Andre Jute

 

[eBob]

I've recently obtained a second-hand Bafang SWXK and did my first 10 mile round trip commute yesterday. This morning I've noticed that it has leaked in exactly the same way. The controller is limiting the current to 10A and the motor is running very quietly. Perhaps this behaviour is 'normal' for these motors? The oil is clearly coming through the join between the cover and the main body of the motor and is presumably being flung out by inertia as the wheel rotates. My motor has a small hole drilled in the housing just behind this join. I wonder what this hole is for. Perhaps replacing lost oil?

Bob

 

[eBob]

I've recently obtained a second-hand Bafang SWXK and did my first 10 mile round trip commute yesterday. This morning I've noticed that it has leaked in exactly the same way. The controller is limiting the current to 10A and the motor is running very quietly. Perhaps this behaviour is 'normal' for these motors? The oil is clearly coming through the join between the cover and the main body of the motor and is presumably being flung out by inertia as the wheel rotates. My motor has a small hole drilled in the housing just behind this join. I wonder what this hole is for. Perhaps replacing lost oil?

Bob

 

[eBob]

I see from your posts elsewhere that you think the hole may be a (blocked) breather hole. That's a nice theory, but if the hole gets blocked that easily, it's not an impressive design. And why is there so much oil sloshing around inside anyway?

Bob

 

[ade]

i have the same motor on one of mine there is no oil inside like that inside you have the clutch set up and gearing which are lightly greased at the factory so it is likely to be grease & water mix but this may indicate water has got inside the motor and is flushing out along with the grease hence on the outer caasing

 

[flecc]

They can leak water in, rather more on the side entry cable models than the spindle entry ones. I'd guess this is a water and grease mix, emulsified into a thick dirty oil by the gear tooth action mixing them.

 

[shemozzle999]

I think the breather hole you refer to is in fact a threaded hole to take a small grub screw which locks the screwed in side cover from unscrewing, so I don't think that is your source of the problem, but it could be they have applied excessive thread sealant and it is being thrown out by inertia as the wheel rotates.

 

[KirstinS]

They can leak water in, rather more on the side entry cable models than the spindle entry ones. I'd guess this is a water and grease mix, emulsified into a thick dirty oil by the gear tooth action mixing them.

Really ? thanks Flecc - I'm fitting a 8fun kit that has a side entry wire. Any recomendations on how to better weatherproof ? bit of epoxy, sugru or other sealant ?

thanks

 

[flecc]

I don't think it's possible to improve on the makers arrangements Kirstin. It only seems to be a small minority which suffer this and I suspect it's often when they've been exposed to extremely wet conditions like parked outdoors. I've not suffered this, but the very occasional owner with the same motor as mine has, so I think it's not a big issue in most cases.

I'm not very familiar with your motor model, but the potential entry points are the static to rotation side plate bearing point which obviously can't be sealed since one must turn freely, and the other side smaller bearing housing. On the spindle entry models I used to seal the cable entry with extra silicone rubber since the amount applied in manufacture wasn't always adequate, and plug the bearing housing ends with some thick grease to deter water entry.

 

[Deleted member 4366]

Don't forget about the 6 disk brake screws that have to be sealed whether you have a disk or not.

 

[Woosh]

Dear Andre,

One of our technicians here thinks that the cover seal is broken, perhaps the previous owner has opened it and not replaced the seal when they put the cover back.
You'll need a special tool to close the motor cover properly.
If it's running OK, best leave it alone, there is plenty of grease inside.

Regards

 

[eBob]

Thank you all for your helpful suggestions. My favourite theory is flecc's; that the leaking 'oil' is an emulsion of grease and water. I'm hoping that the water will eventually evaporate, leaving most of the grease inside. Certainly, the amount leaking out is quite small.

Bob

 

[eBob]

The post that I made a couple of weeks ago hasn't turned up yet, so I'll try again:

Thank you for all the helpful comments. Flecc's suggestion about the water/grease emulsion sounds the most plausible to me. Does anyone know where to get suitable grease for such a motor? I believe there are nylon gears inside.

Bob

 

[chain]

I've just seen this thread again.

It turned out Hatti's suggestion to do nothing was good. I did nothing, whatever the black stuff was -- Flecc's suggestion of water and grease beaten into a nasty black emulstion by the gears seems good -- stopped coming out almost immediately, and the motor lasted about 4000km of pulling an eighth of a ton up constant hills -- there are no safe flat roads for cyclists where I live. There is no indication that the motor suffered or died from this glitch in its very early life; it died after loud rattling inside the case, presumably broken or worn or melted gears, and some of the external excess wiring bundled into a bag was badly burned, which might have scrambled the controller. In any event, the effect of not having enough grease would have manifested itself long, long ago.

4000km at about 16 pence a kilometre seems to me a satisfactory life and cost, after making allowance for having a battery that seems good left for my next motor. I've bought and fitted a stronger but more than twice as expensive Bafang BBS01 midmotor, and we'll see how long it lasts. (It is immediately obvious that the QSWXK front motor was a much more refined installation.)

Thanks to all for their help.