Help - how to remov...
 

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[Closed] Help - how to remove this bottom bracket

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 Aus
Posts: 1522
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Topic starter
 

It's an old Mongoose BMX with a very grumpy bottom bracket ... but I'm stumped, how to remove? Looks like this:

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[url= https://live.staticflickr.com/65535/49869849816_8e4c10aae4.jp g" target="_blank">https://live.staticflickr.com/65535/49869849816_8e4c10aae4.jp g"/> [/img][/url][url= https://flic.kr/p/2iYQ1UQ ]20200508_114134[/url] by [url= https://www.flickr.com/photos/46083140@N06/ ]aus23[/url], on Flickr


 
Posted : 08/05/2020 11:48 am
Posts: 751
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Bash it out. It looks like a Spanish BB. A couple of good hits with a hammer should sort it.


 
Posted : 08/05/2020 11:50 am
Posts: 10942
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Remove the axle and gently tap the bearing out from its other side?


 
Posted : 08/05/2020 11:51 am
 Aus
Posts: 1522
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Topic starter
 

Thought that and have tried 'gentle' tapping of the axle (not the bb itself) to see if it would budge ... but no joy.

The bearings were horribly gummed up do guess it's pretty seized...


 
Posted : 08/05/2020 12:02 pm
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Put a bolt into the end of the axle to avoid wrecking it. Put the frame on two blocks of wood so they are supporting the bearings on the other side. Smack the end of the axle really hard with a big hammer. When you hit things with hammers, you need to do it like you want to really hurt it. A lot of people confuse "tapping" with "hitting".


 
Posted : 08/05/2020 12:24 pm
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Actually, I think you'll need to support the BB shell, not the bearings. Whatever the case, you'll feel good after hitting if for a while.


 
Posted : 08/05/2020 12:27 pm
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support the BB shell, not the bearings

you may find that the axel will want to take the bearing out with it. So support the frame is maybe the best bet here. #not a bike mechanic#


 
Posted : 08/05/2020 12:32 pm
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Can't remember is Spanish BB's have a step in the axle? I thought they were straight and you spaced the axle to fit?

Either way, support the frame as best you can, put the bolt back in the axle to protect it, and smack with a hammer.

Either the axle will come out, or it'll push the bearing out the other side.


 
Posted : 08/05/2020 12:39 pm
Posts: 21461
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Looks like it's press fit. I'd wager there is a shoulder on the axle that each bearing sits against.

Option one. **** the axle. Then **** it again, and again but this time like you mean it. Bolt in the end if you want to save the axle.

Option two. Find a cup with a hole in the bottom that sits on the BB, but clears the bearing. With some threaded bar, a few nuts and washers, wind it out.


 
Posted : 08/05/2020 12:40 pm
 Aus
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Topic starter
 

Thanks, and I'm clearly in the tapping camp rather than 'hitting'. It was a rusty mess so fearful!


 
Posted : 08/05/2020 2:40 pm

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