Snapped crank bolt. Help urgently required!

[pedalsheep]

HELP! I've just snapped off my self extracting crank bolt in my cack handed attempts to remove it. What can I do, apart from cry?

[thirdcrank]

How much of the bit still in there is exposed?

[pedalsheep]

Not much, I've snapped the head off. I also don't have a crank puller that would fit TA. Plus I've just lost what little confidence I had in my ability as a mechanic.

[thirdcrank]

If there's not enough left to grip it with a suitable tool, then afaik the normal method with anything like this is to drill a hole in it and use a screw extractor. These are widely advertised, but not much use if you have lost confidence. (I'm lucky in this respect in that one of my sons is a mechanical fitter.)

[pedalsheep]

Thanks Thirdcrank. This is my pride and joy Roberts and I'm not prepared to risk wrecking it any further, much less stressful to let them sort it out.
The crank is still firmly attached so is it still safe to ride?

[Vladimir]

Thanks Thirdcrank. This is my pride and joy Roberts and I'm not prepared to risk wrecking it any further, much less stressful to let them sort it out.
The crank is still firmly attached so is it still safe to ride?

sorry of this doesnt help, but I would take it straight to a good LBS and get the to deal with it! they might have to resort to sawing off the crank at the BB spindle and then replace the BB?...

[jb]

How did you manage to break it? you must have the strength of a gorrilla.

[thirdcrank]

I've never been in the position of having to ask a bike shop to sort out something like this for me (my own disasters have affected other parts of the bike.) If you have classic TA equipment, I'd check with a bike shop what they would be able / prepared to do. With a lot of bike parts, removal by destruction may be the most cost-effective option but that doesn't necessarily apply if the component will be irreplaceable with a matching component, rather than an equivalent.

IME, a suitable garage might be able to help with something like this. I don't mean a main dealership or an Arthur Dailey outfit but somewhere with a good reputation for sorting out cars. They'll probably have plenty of experience of removing sheared off bolts etc.

[531colin]

If you have snapped the head off the bolt, the only way I can think of this could have happened is the threaded bit of the bolt was rusted fast into the BB spindle, and you wound up the bolt so much that it sheared, which is quite impressive, really. Remind me not to arm wrestle with you.
AFAIK the extractor thread was an unusual size in TA "Cyclotourist" cranks, isn't the modern stuff standard thread?
Presumably you are taking it to bits to replace something?
That would influence how I would proceed.

EDIT...there are crank pullers that don't use the thread in the crank, but I've no experience....

[Brucey]

That sounds like rotten luck; which way were you turning it when it failed?

I can just about see how the head of the bolt could come off if you were turning it CW, but I can't see how you could do this in an ACW direction.

If the crank is still in place and the bolt head is retained by the collar, it could be that the thread has just stripped on the bolt.

I must say that I don't have great confidence in self-extracting crankbolts if they are being used on cranks that have been on for a while; the loads in the bolt are considerably higher than those seen in any extractor tool.

if you can post any pictures this might help.

cheers

[tatanab]

the only way I can think of this could have happened is the threaded bit of the bolt was rusted fast into the BB spindle.

It was only 4 days ago that Pedalsheep was asking how to fit these viewtopic.php?f=5&t=65894 , so I do not think that could be the problem.

I have 4 machines fitted with self extractors and they have been in use for 15 years with no problems. Not TA ones I admit. So I am a bit flummoxed by this.

[Mick F]

Which crank is it that's stuck?
Hopefully, it's the LH crank and you can take off the RH ok.

If so, it may be possible to remove the LH and BB as one piece. If you can get them out, they will be easier to work on.

[pedalsheep]

Thanks all. I was removing the black cranks ( I had never wanted black in the first place but couldn't get 165mm in silver at the time) cos I'd fallen in love with a pair of identical silver ones (sad, I know). I was also changing the bolts to ones with a silver dust cap to match and asked about fitting them just to make sure I'd got everything right.

I tried to remove the LH crank with a large 6mm hex key but altho it unscrewed (turning anticlockwise) a little way it then became tight again. I put a post asking for advice and tatanab said (if I understood correctly) that this was it hitting the dustcap and I would need to apply considerable force to the push the bolt out of the crank. So I did. As a 5'4" woman I never dreamt I could produce enough force to snap a bolt! I understood that its a standard RH thread on both sides, I hope this is correct and I wasn't trying to turn it the wrong way! Tho as I say it did turn a little way before becoming tight again so presumably this is not the case.

It was fitted by Roberts when I had a new bottom bracket about 3 years ago and has since covered about 24,000 miles. My LBS seems to know less about such things than I do so I think my best plan is to pay Roberts to sort it out for me but they are closed on Mondays.

Is it safe to continue to ride it? The crank is still firmly attached.

[Brucey]

well you will soon find out if the crank is going to come loose, but it may not happen if they have been on for that long.

So does the bolt head just turn freely now or is it just tight? If the latter it may be possible to retighten it.

BTW there are many repair strategies depending on what has happened exactly.

cheers

[andrew_s]

Is it safe to continue to ride it? The crank is still firmly attached.

It's OK for as long as the crank remains firmly attached.
However it is possible that the crank will come loose after a while. Riding without crank bolts is one way of getting cranks with broken extractor threads off.
If you ride with the crank loose, you will damage it so that it won't remain properly tight in future, and it will come off some time later (obviously).