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I have an aluminium frame Raleigh bike that's been stuck at the back of my garage for a few years now. It has a wobbly bottom crank. I assume the bearings have gone, but A; I don't have the tool to get the crank out, and B; I don't even know if the crank can be replaced.

It has square things that the pedal stems attach to each side, and after I managed to force the pedal shafts off the crank, there was a thin nut (lock nut?) which I removed from the protruding thread. I don't have a picture currently, but the right side(where the thin nut was) looks like the left side of this picture;

enter image description here which is a Tredz.co.uk Raleigh crank.

So how do I find out which crank I need and what tool I need to remove the old one? Also, do I need any extra tools to install the new one?

I'd love to get the bike working again, and the cranks seem to be pretty cheap.

Edit:

Here are the photos:
enter image description here enter image description here

Update:

Thanks to you guys I could move forward with a better understanding of what I needed to do. For clarity, here are some better pics of the bike and the removed BB:
(click for original size)
enter image description here enter image description here enter image description here enter image description here enter image description here
I mistakenly thought it was a Raleigh, but that was my other bike. This one is a Radford. The new BB I bought looks a lot like the one I posted first actually. Thanks for the help Guys.

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    I don't think you have what the picture shows. The picture is of a sealed cartridge bottom bracket assembly. These do not have a lock ring. What you see in the picture is what screws into the frame, and that's it; the pedal cranks go onto that, then the crank lugnuts and that's it. If there was a lock ring, I think you have a "pressed cup and cone" style bottom bracket (only seen on either very old bikes or recently made "bicycle shaped objects"). You can replace a pressed cup and cone BB with a cartridge; removing the cup may be difficult.
    – Kaz
    Aug 21 '17 at 23:34
  • The person who made this video (replacement of cup-and-cone with cartridge) found it necessary to use a special (evidently custom?) tool to grab onto the cup-and-cone bottom bracket's cup to remove it. youtube.com/watch?v=_pE6oXMNv24
    – Kaz
    Aug 21 '17 at 23:35
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    Can you include a picture of the bottom bracket so the type can be identified?
    – Argenti Apparatus
    Aug 22 '17 at 0:04
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    There are 4-5 different ways that BB cartridges are installed, with aluminum frames more likely to have an odd one.
    – Daniel R Hicks
    Aug 22 '17 at 2:36
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    @n00dles bottom brackets are threaded in the correct direction so that the mechanism of precession, as the cranks are pedaled, acts to tighten rather than loosen. Maybe the locknut prevents this process from tightening the BB too much over years of use (rather than loosening), so that it's not so hard to remove?
    – Kaz
    Aug 24 '17 at 18:30
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What you have in the picture is a cartridge-style bottom bracket which contains the bottom bracket bearings. What you called the 'pedal stems' are the cranks.

Cranks should be removed from the square tapers on the bracket shaft with a special crank puller tool such as the Park Tool CWP-7. If you forced the cranks off by other means you have possibly damaged them. If re-installed on a bottom bracket they may keep working loose.

The bottom bracket is removed using a bottom bracket tool such as the Park Tool BBT-22 that fits into the splines in the cartridge body.

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    Because n00dles removed some kind of lock ring after the pedal cranks, I suspect his bike might have a cup-and-cone bottom bracket.
    – Kaz
    Aug 21 '17 at 23:36
  • @Kaz, yes quite possibly
    – Argenti Apparatus
    Aug 22 '17 at 0:02
  • Yes, it was a nightmare getting the cranks off, I hammered them while using a wood cushion, but they wouldn't budge, so in the end I levered them off as evenly as I could with a chunky old masonry chisel! I wondered what the threads were for. I'll do it properly next time. The bike is over my dad's atm, so I'll add a picture in a couple of days, maybe you could advise me further then. Thanks.
    – n00dles
    Aug 22 '17 at 0:53
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    @n00dles yeah that's the wrong tool for the job. But what's done is done, so best now is work on the bottom bracket. When that's fixed refit the old cranks, and if they're sloppy then hunt out some replacements.
    – Criggie ♦
    Aug 22 '17 at 0:54
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    With the crank press (misnamed "crank puller") tool, you would have been amazed at how easy it is to get a pedal off. Some of them come with an integrated wrench. Just screw the press into the pedal crank, then turn the wrench so that the tool's pin exerts pressure against the bottom bracket axle. You might have to put your weight into it during the critical unbinding moment, but that's about it.
    – Kaz
    Aug 23 '17 at 21:32

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