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I recently attempted to rebuild a sealed cartridge Shimano LP25 bottom bracket. These are meant to be replaced when worn out, but I thought: if someone on YouTube can do it, I can too. The problem is that the top bearings no longer fit, as the first picture illustrates. I am completely certain that these are the exact bearings I removed from the top fixed flange race when I disassembled the bracket. My question is: what exactly is going wrong?

Bottom Bracket Bearings

Bottom Bracket Disassembled

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    It looks to me like you have too many balls, or the wrong size ones. – Daniel R Hicks Jun 21 '19 at 0:36
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    When did you remove the balls? Was it after the axle was extracted? Feel inside -- is the bearing cup indented into the side of the housing (similar to the indentation seen on the bottom of the axle)? If so, you probably need to "glue" the balls into place inside the housing before you insert the axle. – Daniel R Hicks Jun 21 '19 at 0:56
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    Well, how did you ever get the axle out?? Did you have to force it out, or "unscrew" it against the balls? (And what did the guy on Youtube do?) – Daniel R Hicks Jun 21 '19 at 1:26
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    Give us a picture of the inside of the housing, at a slight angle so that we can see the inside profile. – Daniel R Hicks Jun 21 '19 at 1:27
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    @Daniel R Hicks: I feel really embarrassed right now, but the diagram of the bottom bracket I made when I disassembled it had the fixed flange backwards. When positioned correctly, I was able to reassemble it. It works better now than the new $30 Shimano replacement I picked up after thinking reassembly would be futile. Thank you for your patience. – Daniel Portin Jun 21 '19 at 3:20
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I was attempting to insert the fixed flange onto the spindle incorrectly, the result of a poor diagram made when disassembling the bracket. If anyone else finds this post and needs help reassembling a similar sealed cartridge bottom bracket, here are step-by-step instructions. I wiped down the components before taking the pictures for clarity.

  • Insert seal (notched side down) and pack large bearings onto spindle cone.

enter image description here

  • Drop fixed flange onto spindle and pack small bearings.

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  • Insert cone, lock washer and hex nut onto spindle.

enter image description here enter image description here

  • Reseal fixed flange (notched side up)

enter image description here

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    Great work - thank you. Feel free to have a go at answering any other questions that look interesting, and welcome to Bicycles.SE. – Criggie Jun 22 '19 at 3:55

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