GoldenMotor.com Forum
General Category => Magic Pie & Smart Pie Discussions => Topic started by: Adamsavage79 on April 24, 2020, 03:32:00 PM
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Is there a practical way to replace the bearings on the Magic Pie 5 motor ? Looking for a video or some sort of schematic on how to do this.
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To replace the bearings you will need to remove both side covers from the motor, but it is better to do one side at a time so that the stator and axle are properly supported inside the hub.
The bearing on the MP4 and MP5 are exactly the same size as the MPIII bearings shown below:
(http://www.arhservices.co.uk/GoldenMotor/MagicPiebearings.JPG)
The freewheel side cover can be removed complete with the freewheel still attached if you don't have a freewheel removal tool, but it might make it more difficult to drift the bearing from the cover with the freewheel still in place.
If you are using a slide hammer and bearing puller kit you shouldn't have to remove the freewheel unit anyway.
You can remove the brake disc and cooling fan assembly from the side cover as a single item, so don't bother removing the disc from the cooling fan assembly.
The controller should not need to be removed from the stator housing as the cover and bearing should slide over it.
I've never had to remove the large bearing from the side cover, but I suspect that a suitable bearing puller or a special drift may be needed to extract it, probably combined with some penetrating oil and a bit of heat.
If the bearing is really tight inside the cover, a manual or hydraulic press may be required. :-\
Check out this post (https://goldenmotor.com/SMF/index.php?topic=4616.msg26698#msg26698) for more details.
Alan
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That's a massive bearing! That's insane! That large bearing is on the wire side, so the wires should not get in the way ?
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UPDATE: I tried go local for the bearings, but they wanted too much for the large bearing. $250 plus! I went with CDN website instead. These are the ones I ordered, per the picture above. I ended up paying extra for Fed Ex, because with Canada Post, it could be a month or more before it shows up, so that isn't an option for me.
https://www.bearingscanada.com/ProductDetails.asp?ProductCode=6302-2RSJ-EM-Quality-15x42x13
https://www.bearingscanada.com/ProductDetails.asp?ProductCode=6917ZZ-Shielded-85x120x18-Ball
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I tried go local for the bearings, but they wanted too much for the large bearing. $250 plus! I went with CDN website instead.
That's very cheap compared to the food grade bearing at a mere $1,120.44 each. (https://www.bearingscanada.com/S6917-2RS-Food-Grade-Stainless-Steel-Ball-Bearing-p/s6917-2rs%20food.htm)
Is there a particular reason why you opted for the metal shielded version of the large bearing instead of the rubber sealed version (https://www.bearingscanada.com/6917-2RS-Sealed-Bearing-85x120x18-p/kit14022.htm)?
Alan
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That would be by mistake. I didn't catch that. I should see if I can change my order.
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I was able to switch out the bearing for the rubber one, so that's a good thing.
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Hi Alan, I'm expecting my bearings any day now. I was just going over instructions how to replace the bearings. The freewheel side has TWO bearings, and the smaller one fits inside of the larger one ? The controller side has a large bearing, that looks like you can just repack with grease ? I'm wondering if I can get away with repacking, vs removing the bearings. I don't have a Metal drift or a bearing puller, let alone a slide hammer.
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I have not come across a Magic Pie 5 with dual bearing on the freewheel side, unless GM have modified them to take a cassette like the Cassette version of the Magic Pie Edge (https://goldenmotor.com/SMF/index.php?topic=6093.msg34135;topicseen#msg34135).
This is what the single axle bearing on the freewheel side cover Of the Magic Pie 5 looks like when viewed from inside:
(https://i.imgur.com/R35XN8c.png)
Yours shouldn't have the end of the axle poking out of the centre of the bearing like mine does in the above photo, unless you have also placed the cover backwards onto the axle to take the photo. ;)
Are you able to post a picture of the "TWO bearings" on the freewheel side of your MP5?
With regards to repacking the large bearing with grease, this should be relatively easy to achieve if it has the rubber seals that can usually be prised out quite easily.
However, if it has the metal shields, these can be more difficult to remove without damaging the thin metal shields, another reason for using the rubber sealed bearings. ;)
Alan
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Soon as I get my bearings, and take a look @ the motor. I believe I have something similar to a metal drift, but mine have more pointy end. I believe Ottawa Fastener would have one at worse case scenario. Best case is everything is rubber sealed, and I have two spare bearings for just in case sort of thing. I like to have spare parts, so not at all a loose.
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I got both bearings today, but I feel like I'm missing details. It's clear one bearing will not fit inside the other, so there clearly something else between them. Could I get a break down of what I would be looking @ when I remove the cover ?
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If you remove the freewheel side cover you will see this:
(https://i.imgur.com/UlkxygC.png)
And this is a close up of the small bearing inside the freewheel side cover:
(https://i.imgur.com/oq4zfVp.jpg)
This is where the small bearing locates onto the axle:
(https://i.imgur.com/qL0ofh2.png)
If you remove the controller side cover you will see this:
(https://i.imgur.com/eNUvMrx.png)
And this is what the inside of the controller side cover looks like:
(https://i.imgur.com/7gFqf0F.png)
The stator/axle assembly (and possibly some spacer shims on the freewheel side) is what goes between the two axle bearings:
(https://i.imgur.com/8o4qAv4.png)
The large bearing fits over the outer surface of the controller housing.
Hopefully it will all will become more obvious when you remove the covers.
Alan
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Ok so the small bearing on the freewheel side, and the large one is on the controller side. What is throwing me off, is the extra "rings" per say, but I have a better understanding now. I will charge the batter up tonight, then bring it down into living area, and possibly try and take covers off ? I'm just nervous doing this, as I'm worried it will be difficult and or complicated. There is also the worry I could dmg something as well. I COULD get my bike mechanic to do it, when he rebuilds my wheel. He might have more tools and such. I definitely want to try and take the covers off and have a peek inside, then go from there. If I don't feel comfortable doing it, I will leave it alone. The bike still fully usable, it's just very loud the wheel and it's annoying.
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I found a good video that shows how the motor side cover is removed.
https://www.youtube.com/watch?v=oNp_qAeBH9Y&t=577s (https://www.youtube.com/watch?v=oNp_qAeBH9Y&t=577s)
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I finally got around to replacing the bearings. I'm halfway done and I don't think I can go further. I can't remove the controller, as the screws are rusted in pretty good. I would strip the head trying to get it out, which isn't a big deal, as I have a screw extractor. However, if they won't budge, there is no point and trying that either. I was able to get one screw out, so I can take that and get a replacement. All I did for the freewheel side was remove the screws, and gently pry it open with a flat head. Then slide the spacers off, and then I was to simply slide the cover off. With a bit of fiddling around, I got the bearing out. I think I just stuck my finger in and it came out. The replacement one took little more effort. I don't have a rubber hammer, so I folded up some rubber and gently taped the bearing into place.
As for the otherside. It's not coming out. I whacked it pretty good with a piece of wood and hammer, and it moved outwards little bit, but not enough to get my flat in. I also had the side effect of it sliding down. I noticed when I tried to put the screws back in, they were not lined up. Thankfully, I knew which direction I needed to go, as I marked the wheel with a permanent marker. I grabbed a microfiber cloth and tried to turn the cover back, but went the wrong direction. So it ended up sliding in the wrong direction. I was able to turn it mostly back. I then took my flat head and gently tapped on the heatsink of the controller, until everything lined up.
I put everything back on the bike, gave it a quick test spin to make sure I didn't damaged the wires inside, and everything seems to be ok. From the looks of it, the large bearing is rubber sealed ? It might possible to access the seal and bearings, from the freewheel side, without needing to remove it.
EDIT: Couldn't I just tap out the cover from the freewheel side ? Gently tap at it with a piece of wood or something, so as to not damage the inside of the cover ??
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I can't remove the controller, as the screws are rusted in pretty good. I would strip the head trying to get it out, which isn't a big deal, as I have a screw extractor. However, if they won't budge, there is no point and trying that either.
You shouldn't have to remove the controller as the bearing and cover should pass over it. The outer diameter of my controller was ~2mm smaller than the inner diameter of the bearing. ;)
Couldn't I just tap out the cover from the freewheel side ? Gently tap at it with a piece of wood or something, so as to not damage the inside of the cover ??
That should work to remove the cover and bearing but be careful not to damage the stator or magnets as they will no longer be kept apart if the freewheel cover is not fitted.
Try and keep the wooden drift (Piece of 1" x 1" or old broom handle etc.) as close to the bearing as possible and work your way gradually around the hub (or alternate the taps from side to side 180 degrees apart) to avoid tilting the bearing causing it to jam on the stator/controller housing.
If you heat up the side cover with a hairdryer or heat gun to expand the aluminium, you may be able to drift the cover off on its own, leaving the bearing behind, as drifting the bearing off the stator should be a lot easier than struggling to drift the bearing out of the cover after the cover and bearing have been removed as a single item. ;)
I would thread an axle nut onto the controller end of the axle (until it is flush with the outer edge of the axle) and then place the nut on a hard surface (using a scrap piece of wood to protect the surface) and then pack the wheel (not the side cover) so it is kept nice and level using blocks of wood, cardboard boxes or piles of books etc. while you drift the cover towards the hard surface.
This should hopefully prevent the stator moving in and out of the magnets each time you tap the drift on the inside flange of the the cover (the machined surface surrounding the outer race of the bearing).
Alan
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Maybe I will try that. It does come out abit, but I don't recall if it was clear enough from the rest of the wheel to do heat it up, to get it off.
I should also add that the motor is still quite loud and I'm not sure where the sound is coming from, or why. All I know is that it was fine until I was biking in the rain one day. When I replace the bearing and spun the cover on my finger, it was silent. So it must be coming from the controller side ? Can a bad bearing even produce that much noise ? It did seem like the sound was noticeably louder on the controller side, so perhaps it is that bearing.
Here is a quick video clip of what it sounds like: https://youtu.be/9TZMPxa-4Lg
Refresh my memory on how to remove the large bearing, once the side cover is removed ?
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The noise in your video is definitely a bearing noise, but I've heard much worse. In fact, my freewheel bearings made a lot more noise than that. ;)
My noisy freewheel bearing was easy to identify as the noise would disappear altogether while I was pedalling but started again as soon as I stopped pedalling while the bike is still moving.
The small amount of noise coming from the bearings is being amplified by the large side cover because it tends to act a bit like a loudspeaker cone and will produce a much louder noise.
Refresh my memory on how to remove the large bearing, once the side cover is removed ?
I've never had to remove the large bearing from the side cover, but I suspect that a suitable bearing puller or a special drift may be needed to extract it, probably combined with some penetrating oil and a bit of heat.
If the bearing is really tight inside the cover, a manual or hydraulic press may be required.
It would probably be much better if the side cover could be removed leaving the bearing behind on the stator assembly, so that you could then drift the bearing off the stator by tapping the bearing with a solid drift.
It might be possible to initially drift the cover off the bearing by tapping in the same position between the same two stator spokes, but rotate the cover each time to gradually work all around the bearing housing part of the side cover. This will hopefully cause the bearing to tilt and jam onto the stator housing allowing the cover to be drifted off it leaving the bearing behind. :-\
Then you would need to drift on the opposite side side of the bearing to unjam it and then keep alternating from one side to the other until the bearing can be drifted all the way off.
However, if the cover will only come away complete with the bearing, it might be possible to place it in an oven and heat it up to expand the aluminium enough until the bearing simply falls out, although I don't know what temperature the paint will be able to withstand. ::)
Unfortunately, if the bearing has to be drifted out, there is very little of the bearing that you can apply a drift to as the inner diameter of the cover is not much larger than the inner diameter of the bearing, and the bearing will probably have a radiused edge making it very difficult to drift against.
Good luck, and please let us know how it goes.
Alan
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I'm going to leave this to my bike mechanic I think. He needs to rebuild the wheel anyway, so the wheel will be likely removed from the bike anyway. I recall that I was able to get the cover to come off abit, but not enough to get in with any of my tools. It was not far enough away from the rest of the wheel, for me to heat it up with my heat gun. If the cover comes off with the bearing, it looks like you can just tap it out gently bit by bit ? Or like you said, heat up the cover around the bearing so it expands just enough, that the bearing would either fall out or be much easier to remove.
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Seeing as I have the controller cover off and I'm in the process of removing the controller, how difficult would it be to get the large bearing out ? I can see that the controller fits inside of it, but I have no idea if it will budge. Also, could I not put bearing grease around the outside of the controller, too prevent water etc from getting into the bearing and such ? I can see the dried water or salt, now that I have the controller cover removed.
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I presume you have only removed the cooling fan and brake disc mount as the "controller cover" (the outer part with the cooling fins) is part of the controller , which you're still "in the process of removing".
I would try to remove the side cover leaving the bearing behind and then apply some penetrating oil between the bearing and the controller housing before trying to drift the bearing off as previously described (https://goldenmotor.com/SMF/index.php?topic=6940.msg38034#msg38034).
Adding some grease around the outside of the controller housing should definitely help to prevent both water ingress and further corrosion from the electrolytic process that will take place if saltwater gets between the aluminium housing and the steel inner bearing race.
You might want to also take a look at this post (https://goldenmotor.com/SMF/index.php?topic=7029.msg38263;topicseen#msg38263). Although the stator assembly and side cover is a lot different on the Smart Pie compared to the Magic Pie, the technique for removing the bearing should be very similar. ;)
Alan
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I realized after, I still have the outside controller housing as well. I don't see how I would be able to pull the bearing off with that in the way. The only way would be to get the entire side cover off. Spring project maybe, or see if I can find someone in Ottawa that would be willing to do it.
Also, yes I have to still remove the controller. It does jiggle, so I just gotta play around with it. I had a stripped screw which I was unable to get out, so I had to pay someone to get it out for me. I just got the wheel back yesterday. I will get around to removing the controller this weekend sometime.