Cannot find the main drive bearing on 2nd Gen motor

Dmitri

Active Member
My 2nd gen motor became noisy and the internets say it's due to a dying main drive bearing. So I bought all the tools and the bearings, removed the crank with the crank puller, then removed the sprocket and... I cannot find the drive bearing to replace.

Can someone tell me where the main drive bearing actually is? Am I supposed to open up the motor itself? (Yes I tried Googling it, no clear results.)
 

TrevorB

Active Member
If its less than 2years old then should be covered by warranty.

You will need to dismantle motor, couple members on pedelec forum have done it and provided info on doing it along with source for bearing. Seem straight forward.

A good writeup with lots of photos would be appreciated if you are successful.

A quick test before you start, is give crank good spin without chain. If OK should be good for 2-2.5 turns before stopping.
 

Dmitri

Active Member
If its less than 2years old then should be covered by warranty.
Haha, in theory yes, however the shop that sold me the bike told me they no longer sell bikes and to contact Bosch directly, and as for Bosch, well, they just want me to go away:

bosch ebike customer service.png
 
Haha, in theory yes, however the shop that sold me the bike told me they no longer sell bikes and to contact Bosch directly, and as for Bosch, well, they just want me to go away:

View attachment 23342
Hi Dmitri,
I have a page and site to help people with this issue. I have attached a pdf that should help you identify your bearing. Hope it helps?
 

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Dmitri

Active Member
@Haibike Rider thanks for this! looks really complicated though. And I don't quite understand - are there two bearings that can go bad there? The one that I think is wrong on my bike is the drive side bearing, but people refer to it as the 'main drive bearing'... that's the one I bought.

The suggestions to use a punch or chisel to remove the bearing are also a bit scary.
 
The main motor bearing is, or should be a 5 minute job. Just remove the right-hand engine case (provided you have the crank release tool and drive sprocket tool). This bearing is a very thin bearing and generally drifts out the housing quite easily. I understand that most people don't have access to bearing drifts and power presses but as long as you are careful you can normally get away with a suitable sized socket to knock the bearing from the housing and a socket that fits the outer race to drift it back in. The only mention of a chisel is to release the security nut for the torque sensor, you wont need to do this if you are only doing the main motor bearing. See step 5 on the how to pdf.
If you only have motor noise you have bought the right bearing. If you have play in your crank i.e. you can get hold of your crank arm/pedal arm and feel movement if you push and pull it in the direction of the bike, then you probably crank bearing failure.

If you're local I can offer a fitting service. My address area is on the site.
 

Alaskan

Well-Known Member
Use the correct diameter socket wrench (without the ratchet handle}, the same diameter as the outer race of the bearing. Light steady taps on the socket should do it. Also a short length of pipe the same diameter will work
 
Hi All,
Just to keep you up to date. I have now sourced, or had made, just about every bearing in the Bosch Active and Performance line and CX motor. I have also added a video on how to change these bearings. The link can be found on my "how to" page. https://www.performancelinebearings.com
Thanks for anyone following this and please share if you can.
 

Dmitri

Active Member
Hi All,
Just to keep you up to date. I have now sourced, or had made, just about every bearing in the Bosch Active and Performance line and CX motor. I have also added a video on how to change these bearings. The link can be found on my "how to" page. https://www.performancelinebearings.com
Thanks for anyone following this and please share if you can.
Thank you! However, I think I speak for everyone on this forum when I say... we don't have industrial presses sitting at home, and applying 2.5t of pressure on a bearing to push it in is unrealistic task unless you have specialized equipment.
 
That is why I offer a fitting service. If it's not possible to send your motor or drive sprocket carrier to me, you could take it to a garage or workshop with press facilities. I'm sorry I can't help any more than this :( But failing all this, you could buy a new motor!