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Discussion Starter · #1 ·
Alright, so I work as a bike messenger in Helsinki and the winters can be quite... salty. And grimy. And gritty.

This has lead to my work bike bottom bracket seizing completely in the shell, both cups. I tried all the usual stuff, soaking in WD-40, bolting on the BB tool, using a long breaker bar but no luck. Or bad luck, actually, as all I managed to do was strip the teeth on both sides of the BB completely. Tool took'em straight off when bolted down and forced enough with the breaker bar.

As far as I can see my only option to salvage the frame is to somehow cut the BB out of the shell. It's a square taper sealed cartridge unit, and I've already managed to get the axle out, but I'm a bit lost for ideas on how to actually get the shell out. The metal is so hard that a hacksaw doesn't even scrape it. Any ideas would be appreciated!

I got some small grinding bits for the dremel, update with pictures coming tonight!
 

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Did you try heat, as in from a torch? Assuming this is a steel frame, applying some heat would/could help break away the rust that's formed. How did you apply the WD-40, did you just try spraying it from the outside or did you use the BB hole and really saturate it to work itsef out? Also, while WD-40 can work somewhat, a spray/lube that is actually designed to help "unstick" stuck parts would be much better.
 

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Discussion Starter · #3 ·
Applied both inside (through the cable guide hole) and out, letting it sit for a few days before trying anything. Didn't try heat as I managed to strip the teeth on my first efforts so nothing to screw out against anymore. Heat's been applied now from a couple of hours of dremelling in the BB shell... :D went to a bike shop I know and they pretty much concluded that different acts of violence is all that's left to do. The reciepe for these acts of violence remained unclear from their explanation though.
 

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EAT MORE GRIME
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air impact wrench with appropriate BB tool should get it out
 

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If the spindle is out and you can pass a hacksaw blade through, you may be in luck. Remove the blade from the saw, pass it through the bottom bracket and reattach it to the saw. This will take some elbow grease, but, make a cut straight down through the cups until you hit the bottom bracket shell. It is often necessary to make a second cut, but this will relieve the tension and the cups should come out. Also, packing in ice can be helpful.
 

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Your issue with removing the retaining rings is likely that the bearings are still intact behind them--home users are unlikely to have tools capable of cutting through the hardened races of the bearings. You will need to use carbide cutting tools to get through the races, and they are going to take time/consume the blade/discs getting through. This is one of those cases where it is not economical to fix yourself if you don't already own the tools.

That said, here's the gist:

Apply copious amounts of penetrating fluid to the shell/thread interface. I don't know what you have where you are, but CRC Freeze-off is a great starter, just maybe not for prolonged efforts. It works best with material differentials (ie: steel 'cup' in an aluminum frame); wear gloves! It literally freezes as it evaporates, hopefully breaking corrosive bonds while it does so, allowing it/other oils to work in.

Your first stop is the LH frame retaining ring; You must break the inner race--start with a carbide scribe to mark your cutting area, then use a carbide cutting blade on a hacksaw/reciprocating saw to get through the inner race. Minor damage to the retaining ring is okay, but try to keep it to a minimum. You can use a carbide/diamond tipped scribe for a rotary tool, too. Once through, knock the inner race off with a punch. It won't take much effort; it will land in/away from the retaining ring. Using a large screw extractor (check the size of the hole in the retaining ring, and choose accordingly...it must be as large as possible. Hardened extractors are brittle, and require a ton of care to not break. You will need a large tap handle, one burly enough for the job at hand, to reduce the likelihood of breaking the extractor (at least 30-45cm).

Once the retaining ring is removed, punch the rest of the stuff away from the RH retaining ring--done best with a slide hammer/blind bearing puller--and get your hands on an EVT fixed-cup remover/its like (using home-made is possible, but the genuine article is up to the burliest tasks). Install it, and go to town.

After removing everything, have the bottom bracket shell faced/chased to remove any bits left over.

It should go without saying that during the process, you should keep applying your penetrating oil. You can make a passable, if irritating to use, oil from 50/50 automatic transmission fluid and acetone. It must be shaken constantly, or it will separate. Kano Kroil, if available, is the best for stuck stuff.

It is best not to approach trying to remove the rings by cutting all the way through...it sounds like a good idea, but is terribly difficult to do in practice. Expect to spend 4-5 hours try to do so carefully...made more difficult by the bearing races still in the retaining rings. Damage to the frame, depending on thickness/material, can be difficult-to-impossible to repair if you go too far with the saw.
 

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Discussion Starter · #16 · (Edited)
get your hands on an EVT fixed-cup remover
Man, that tool looks amazing! Already started down the cutting path yesterday though. It's gone way better than expected albeit veeery slowly, have gotten the plastic cup out and cut the cartridge down to a point where only a lip of the shell (if needed for prying or whatever down the line) and the drive side cup remains. Managed to avoid any major damage to the threads (the worst is pictured), nothing a good chasing couldn't resolve.

Tomorrow it's face-off with the main boss, the drive side cup. Fingers crossed...

This is what's come out so far (minus the plastic cup).


Nothing too badly gone on the threads, mostly minor damage from prying out the plastic cup.


This is what's left to do away with as of tonight.
 

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Discussion Starter · #17 ·
YEEHAAW, IT'S OUT!!! Took me four nights of work but I finally conquered it - without rendering the frame useless in the process! The threads gained a few blemishes on both sides, the worst of which was done to the drive side by trying to drill some relief holes in, way before going down the hardcore cutting path. Bad idea it was, the drilling (pictured below).

Cutting the drive side out was slooow going, especially getting through the cartridge. I did four cuts total, 90 degrees apart. After three cuts the remaining cartridge came out. Once all the way through I was bit disheartened to find nothing seemed to budge. This was my darkest hour, I thought I'd come all the way to the finish line to find it unsalvagable, the cup completely fused to the shell. I pulled a hail mary with an old electronics screw driver, which I used as a chisel and managed to pry one of the quarters of the cup out from the inside. The rest of the cup followed suit easily!

The penetrating oil had seeped quite far into the threads upon inspection. The drive side threads were extremely rusty and nasty. I was afraid there wouldn't be much left to bite onto, but it turned out better than expected after a good once-over with the dremel wire brush tool.

I made a DIY thread cleaning/chasing tool out of some old BB cups and cleaned/chased the threads. The new BB went in without complaint even though the threads don't look very pretty!

Assembled it with A LOT of grease this time, will need to be more rigorous with the BB service in the future. This has to be the most **** job I've ever done on a bike, don't want to ever do it again... HOWEVER, I'm quite pleased with myself for finishing the job and proving (mostly to myself) that it's possible! Just needs a lot of patience.

Tools used;
Dremel, found that narrow milling bits worked the best even though it was slow going. Brushes for cleaning the threads & rust
Hacksaw, for the fine work next to the threads
Mallet and chisels for getting the cups out

The drive side end result;

 

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Congratulations!

I know the feeling, I spent several weeks trying to remove a stuck seat post from a frame I bought. Finally, with a lot of torch work, I was about to break it free and then unscrew it from the frame over the course of several nights.

Here's what she looks like now:

Bicycle tire Bicycle frame Bicycle wheel Bicycle wheel rim Bicycle fork
 

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Alright, so I work as a bike messenger in Helsinki and the winters can be quite... salty. And grimy. And gritty.

This has lead to my work bike bottom bracket seizing completely in the shell, both cups. I tried all the usual stuff, soaking in WD-40, bolting on the BB tool, using a long breaker bar but no luck. Or bad luck, actually, as all I managed to do was strip the teeth on both sides of the BB completely. Tool took'em straight off when bolted down and forced enough with the breaker bar.

As far as I can see my only option to salvage the frame is to somehow cut the BB out of the shell. It's a square taper sealed cartridge unit, and I've already managed to get the axle out, but I'm a bit lost for ideas on how to actually get the shell out. The metal is so hard that a hacksaw doesn't even scrape it. Any ideas would be appreciated!

I got some small grinding bits for the dremel, update with pictures coming tonight!
So I did the exact same thing and I was wondering how you got the axis out?
 
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