I just smashed up my Bottom Bracket...

Bicyclegadabout

...while trying to unscrew it.

I was doing right I think, but 7 or 8 of the splines broke off, and now it's all a bit of a mess.....


What do I do? Please tell me I haven't just destroyed my bike. It's my old mountain bike, I reckon the thing was just old and corroded or something.

Drapper

Bicyclegadabout wrote: »

...while trying to unscrew it.

I was doing right I think, but 7 or 8 of the splines broke off, and now it's all a bit of a mess.....


What do I do? Please tell me I haven't just destroyed my bike. It's my old mountain bike, I reckon the thing was just old and corroded or something.

get a few pics up, you'll get more help that way!

Bicyclegadabout

No chance of pics I'm afraid. Basically, 7 or 8 splines are completely gone and there's a couple of cracks in it. Just on one side.

seamus

Kind of depends on how old it is, and how it's configured. As a rule though, provided you can get the bracket out of the frame, you shouldn't have done any damage to the frame, so should be able to replace the bottom bracket.

You should note that the same rules apply for bottom brackets as for pedals - one side screws out clockwise. Afaik, it's the left-hand side which you screw clockwise to screw it out, but I haven't removed a BB in years, so don't quote me on it. Were you trying to get the left hand side out when it broke?

Bicyclegadabout

It was the non-drive side, which I was turning anti-clockwise as I was facing it.

That's not a great description, but I did as I'd seen it on an instructional video on youtube.

Would I be able to get it out from the other end perhaps?

kenmc

did you try the drive side? it should be reverse threaded, so turn it clockwise to loosen. once you have that out, the lockring should be removeable by hand.
was it metal or plastic? if plastic you should be able to break it out gently, e.g by drilling a load of small holes in the lockring and cutting them out. If it's metal you might be able to 'drift' it out with a small cold chisel or punch, and some gentle hammer-work.

Bicyclegadabout

Right, cool.

It is metal btw.

I'm getting the impression it's not a lost cause then, which is the main thing. I'll take it to the LBS and see what happens. It'll be humiliating but ****it.

flickerx

gadabout, where's that video?

hey rob1891, the bottom bracket on that cracked tomasini frame you gave me is seized up, solid, tried to get it out myself but zero movement - and the shop i brought it into refused to try and remove it for me, because they said the bike was too dangerous to even try to repair..

Bicyclegadabout

There's a few videos. On a Google search it's comes from YouTube, prob best to search for it there. The one I watched one had the Zutons (meh) and The Kooks (ick) on the soundtrack.

rob1891

bike shops are full goons, don't mind them!

Truth be told, I had a good go at removing it myself. A kettle full of boiling water on the shell and then as much force as I could muster, but it didn't budge for me either.

If I had a good bench vice I would have put the removal tool in the vice and then used the rear triangle as a lever to unscrew it. Soak the bb shell in wd-40 or any cheap light oil. You could even give the bb-shell a blow of a gas torch (em, drain any wd40 first, or be prepared for a fire), obviously to get the metal to expand and crack whatever bond has been made.

Heartly recommend the boiling water for lesser problems, it has helped me a fair few times.

kona

I wouldnt use the blow tourch at all unless it was the absoloute last option, as heating the metal will weaken it, cooling too fast will make it brittle, and then because the BB needs to be perfectly round putting too much heat on could warp it.

i take it were talking about a cartridge BB here?

heres the best plan but will have to be VERY careful.

-remove R/H BB

- get a long hacksaw blade and hacksaw.

-put the blade through the BB housing.

-connect blade to saw handle, so you have the BB stuck in the middle of the shell.

-before you cut cover the BB in WD40 or whatever to make it cut easier. cut the offending shell in half VERY VERY carefully keeping a eye on the threads, the cuts will take the forces away from being in a circle and the shell should just collapse, you could cut it into a X which would make it easier again.

- you may need to get the threads cleaned up in a lcb after though:)

rob1891

on the torch ... I was suggesting that to flickerx who has an old steel frame that's already cracked at the down tube.

Should have noted what a bad idea it would be to take a torch to an Alu frame and I'd be a bit hesitant to take it to a undamaged steel frame also.

What kind of bb does the OP have? Sounded to me more like a Octolink/ISIS/ST type with splines on the inside of the lock rings ...

Flickerx is definitely square taper, so no sawing through that ...

kona

rob1891 wrote: »

on the torch ... I was suggesting that to flickerx who has an old steel frame that's already cracked at the down tube.

Should have noted what a bad idea it would be to take a torch to an Alu frame and I'd be a bit hesitant to take it to a undamaged steel frame also.

What kind of bb does the OP have? Sounded to me more like a Octolink/ISIS/ST type with splines on the inside of the lock rings ...

Flickerx is definitely square taper, so no sawing through that ...

i may have gotten the question wrong but doesnt he just want to remove the cup and replace it?? the R/H bit of a cartride is the business end when you take that out its just a plastic cup on the other side???

isis is the same idea.

a cup and cone is pretty much the same except its the L/H that you remove.

okay so we are talking cup and cone with ken and a cartridge with flicker i think.

bicycle,
a adjustable wrench is what you need, you always take the L/H out as the R/H is a BITCH.
i take it lock lock ring is gone.
the best way is to find a way to get the wrench to stop slipping off the BB, i find the best way is a strip on metal with a hole screwed onto the axle.
thn turn it, shock loading with a hammer helps.

if this doesnt work, id go to a hardware and get CO2 and spray that on the metal then beat the **** out of the cup, hopefully with the cracks it will shatter.

flicker the method in the other post should work, although in 5 years of bikes ive only failed to take out 1 BB and that was in a 12 year old MTB that was left it the rain, you maybe unlucky and it could be just welded/seized in there!

rob1891

sorry, just not sure I follow you kona. You want the blade to go through the BB shell, but if it is Square taper you won't be able to fit a blade through the centre of the axle, and with ISIS or Octolink, sawing through the steel axle is going to be a huge job ...

So I was thinking you are talking about an external bearing bottom bracket, i.e. Hollowtech II, where the axle comes out with the crank and you could just saw through the cups ... but given that it is an 'old mountain bike' ... I'm not sure he'd have such a BB ...


edit: posted before your edit kona ...

Bicyclegadabout

Yowzers, things got complicated while I was at lunch.....

It's a shimano bb. it's got 20 splines, which do fit nicely with the Shimano BB remover I got in the Lidl toolkit. I don't really have any more information I'm afraid.

kona

rob1891 wrote: »

sorry, just not sure I follow you kona. You want the blade to go through the BB shell, but if it is Square taper you won't be able to fit a blade through the centre of the axle, and with ISIS or Octolink, sawing through the steel axle is going to be a huge job ...

So I was thinking you are talking about an external bearing bottom bracket, i.e. Hollowtech II, where the axle comes out with the crank and you could just saw through the cups ... but given that it is an 'old mountain bike' ... I'm not sure he'd have such a BB ...


edit: posted before your edit kona ...

its hard to explain without actually taking one apart in front of ya!

on a cup and cone, if you take the L/H cup out the axle can be pulled out.

this leaves the R/H cup and a hole for the axle, its through this hole you put the blade and cut.

same idea with a cartridge, the R/H is the business bit, its a entire cartrigde and axle, when this comes out you are left with a cup on the L/H side, with a hole in the middle.

you wouldnt need to cut out hollowtech as they dont need to be put in as tight.

kenmc

Bicyclegadabout wrote: »

Yowzers, things got complicated while I was at lunch.....

It's a shimano bb. it's got 20 splines, which do fit nicely with the Shimano BB remover I got in the Lidl toolkit. I don't really have any more information I'm afraid.

Oh. now I wonder if this was at least a contributer to the problem - maybe the splines on this were not as deep as the real shimano one, or the tolerances not quite as accurate? Just a thought....

kona

Bicyclegadabout wrote: »

Yowzers, things got complicated while I was at lunch.....

It's a shimano bb. it's got 20 splines, which do fit nicely with the Shimano BB remover I got in the Lidl toolkit. I don't really have any more information I'm afraid.

okay if its a shimano the L/H cup is the easiest to get out, followed by the right, when the bike is upside down, on the L/H cup you turn anti-clockwise as you face it(if im wrong sombody point it out i can never remember!):o

also those BB removers are a bollix to hold in, use the way i pointed out in a previous post to hold it in!

kona

kenmc wrote: »

Oh. now I wonder if this was at least a contributer to the problem - maybe the splines on this were not as deep as the real shimano one, or the tolerances not quite as accurate? Just a thought....

the splines are shallow on all the tools its actually insane how shallow they are, park tools are even short, its the way they designed the BB(shimano what:D:D)

Gavin

kenmc wrote: »

Oh. now I wonder if this was at least a contributer to the problem - maybe the splines on this were not as deep as the real shimano one, or the tolerances not quite as accurate? Just a thought....

No problems using the same tool from the lidl toolkit removing BB from my mtb bike. Just need to make sure it's fully in, apply lateral pressure and then apply turning pressure slowly. I scrapped off a bunch of the plastic splines on my BB too when I first did it. Just have to go through it slowly.

Gav

RtD

kenmc wrote: »

Oh. now I wonder if this was at least a contributer to the problem - maybe the splines on this were not as deep as the real shimano one, or the tolerances not quite as accurate? Just a thought....

Ha, I was thinking the exact opposite, some where along the lines of 'Good stuff, now I know my toolkit wont melt like butter when a bit of pressure is applied.'

flickerx

So, regrettably I couldnt get that bottom bracket out of the frame that rob1891 gave me. I brought it into the workshop with this thread printed off as a guide to what to do. Here's a pic of the frame, you can see the crack in the down tube too:



First up anyway I had a go at putting the BB removal tool in the vice and using the rear triangle as a lever to get some torque. Making sure I was turning the frame in the right direction :-) I had a go and trying to lever it out (after I had soaked it in wd40 the night before). After numerous tries the only thing that happened was damaging the splines, at least six or seven of them snapped off a bit onto the removal tool.



Next we had a go at heating it up and taking it out, and we heated it a good bit so it might crack the bond, but no joy... here you can see it smoking away (possibly burning off some of the wd40 in the middle) but no matter what we did, with the tools, it just wouldnt budge. The edges of it are now damaged fairly badly (I may have taken a hammer to it at one point after everything failed... ) so I just cant see it coming out. The instructor said to get a heavy drill and drill into it, but I dont have one, and also I think the threads in the frame will probably have been damaged by now too... so its staying where it is, shame! I managed to weld the frame back together by brazing, its not pretty, I'll upload the photos from that later in the welding thread...

rob1891

Did you try from the other side of the frame, Kona's suggestion was that the other side is often looser and will come out more easily. At that point you can remove the axle and bearings leaving only the drive side shell in the frame. Then the cup can be sawn through.

Other thing (you might have done already) is when using the bb removal tool is put a quick release through it and through the centre of the bb axle and then tighten it down so that the tool doesn't slip out of the splines. You'll need to loosen it as the shell comes out of the frame.

Rob

flickerx

rob1891 wrote: »

Did you try from the other side of the frame, Kona's suggestion was that the other side is often looser and will come out more easily. At that point you can remove the axle and bearings leaving only the drive side shell in the frame. Then the cup can be sawn through.

Yeah we had a go at both sides, me making sure that I was turning in the correct direction both times. The BB wasnt moving at all...

Other thing (you might have done already) is when using the bb removal tool is put a quick release through it and through the centre of the bb axle and then tighten it down so that the tool doesn't slip out of the splines. You'll need to loosen it as the shell comes out of the frame.

When we were turning it, I had two other people helping, one to put downward pressure and the other to help me turn from the other side of the frame so the centrifugal (or is that centripetal?) force was balanced.. Its just hardcore jammed in there...

Not sure what to do next with it. Its a nice frame, the weld on the down tube wont look so bad when its painted (pics up soon), so if anyone else would like to have a go of removing the BB, let me know...