Bosch Gen4 Seal Service & Grease up

Ark

Active member
Mar 8, 2023
460
386
Newcastle Upon Tyne
I bought a park tools crank extractor because all the vids say you need one for bosch..

Then I looked at my pedals lol..... oh whyte use self extracting cranks :cautious:


BTW, What's the tool called that has the blue handle and basically a hook for removing stuff?

Good video apart from the camera work
 
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RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
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It's just a pick tool & yep, camera work a bit of an aftethought, the GoPro on the chesty & stray left hand not the most helpful but hopefully the main stages are clear. It was Pete the @Bearing Man who impressed the importance of this job onto me. I'm forever grateful to him.
 
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Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
14,021
20,794
Brittany, France
camera work a bit of an aftethought
Nice job !

I thought the camera work created an air of suspense and intrigue at times, with the right music and a bit or work on the lighting it would feel a bit Hitchcock..... What's happening behind the arm .... da da darrr ... It's a SEAL , a SEAL ! Where's he lubing ? It's not one of those types of films is it dear ?
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
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I think you'd judge it each time. The seals themselves are aluminium or steel with rubber covers bonded on to them. They don't wear quickly at all whereas the grease does disperse over time. Can't give a straight answer other than to say my bike has 2k on the clock & I've replaced them once & they're doing fine.
 

Sander23

Active member
Aug 28, 2020
740
457
Belgium
I do this regularly as I do like to wash my bike alot to keep it clean.

It's not that easy as mine has this very stupid pointy circlips with no holes in em wich are very hard to remove
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
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I mention that in the video. The drive side circlip is a different design from the non drive side, on my bike it has bevelled edges which make it awkward to handle. I bought a pair of cheap pliers & ground the tips at an angle to match specifically for the job.
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
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I made a follow up video, closer to the action so you can actually see what I'm doing. Don't get excited, the production values are worse than ever but at least my hand isn't in the way, spoiling all the fun.

 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
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Sure. They're some cheapy Amazon or Ebay circlip pliers. I've added the drive side circlip so you can see what I'm talking about. The bevelled edges of the circlip itself tends to make the pliers ping off as you exert force on it, whereas on the NDS, the circlip has a v shaped indentation so that your pliers stay in place. It is a poor design.

If you struggle to remove this in one move, I've found an effective technique is to get one side out of its slot & onto the spindle, where it will stay, then go in for a second try. Once you have the circlip out of it's groove, it's just a matter of expanding it sufficiently to pull it off the spindle, taking care not to mar the thread on the spindle that your lock ring relies on.

YI955pZt.jpg
T_a1ayh8.jpg
 

Ken

Member
May 30, 2020
53
24
Northumberland
Thanks Rusty, Used all the techniques you suggested and both sides now refreshed. The NDS snap ring pinged off at first attempt and I enlisted my hawk eyed wife to find it among the multi crap in the garage. Progress on the DS was halted by the chainring being virtually welded to the shaft. It has done over 5000mls and much levering was needed to free the micro splines.
cheers, Ken.
 

Tony4wd

Active member
Subscriber
Aug 3, 2022
259
223
Australia
My Cube is 2 years old so I've ordered the seal kit after seeing this thread - seems like a good idea to keep water out of the motor.
Is there a similar process for the Shimano EP8?
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,847
6,886
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Wouldn't know about Shimano motors. Might be something online somewhere. Otherwise, I did this for a friend last week on a Trek with 1000 miles on the clock & the drive side seal cover had separated from the metal inner, so worth checking regularly imo.

T8kgywos.jpg
 

Stihldog

Handheld Power Tool
Subscriber
Jun 10, 2020
3,540
4,964
Coquitlam, BC
My Cube is 2 years old so I've ordered the seal kit after seeing this thread - seems like a good idea to keep water out of the motor.
Is there a similar process for the Shimano EP8?
Do you happen to know the part # of the seal kit? (or a link). My local Trek dealer can’t seem to find it.

Maybe it was mentioned here.
 

Peaky Rider

E*POWAH Master
Feb 9, 2019
847
538
Derbyshire Dales
I've been inspired by Rusty's video to service my seals, but those advertised on Ebay etc seem to have conventional circlips rather than the snap rings shown in the video.
Is this a sensible upgrade adopted Bosch or am I looking at the wrong part?
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,847
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Can you lionk the Ebay listing? Far as I am aware, the only source of kits is Bosch & their distributors eg. The Ebike motor centre etc. So I'm wondering if there are knock offs circulating.
 

Peaky Rider

E*POWAH Master
Feb 9, 2019
847
538
Derbyshire Dales
Can you lionk the Ebay listing? Far as I am aware, the only source of kits is Bosch & their distributors eg. The Ebike motor centre etc. So I'm wondering if there are knock offs circulating.
This is the advert from one of my local bike shops. The illustration seems to be a generic one used in many ads. I'm guessing Bosch realised their snap rings were pigs to get out so switched to conventional circlips.


Thanks
PR
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,847
6,886
UK
That looks much easier to live with! And JE James is obviously a wholly reputable retailer, so it looks like maybe all the techs moaned at Bosch until they changed the circlip. In the instructions Bosch provide, they go out of their way to mention you should only use the circlip pliers illustrated in the document & I couldn't ever find any.
 

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