MegaSack DRAW - This year's winner is user - rgwb
We will be in touch
following on from my fascinating "what bottom bracket" thread from earlier, i have now encountered an obstacle.
I have had the chance to remove the old BB, but with a slight problem: the extractor threads in the left crank are slightly damaged (i don't know how - they were not new and i have not noticed this before) on the outside, so my crank extractor won't engage. there is still about 90% of the thread that would be "good".
i now have a removed BB but with one crank still on the spindle. so i may yet be getting a new chainset to go with the new bottom bracket!
any suggestions on how to remove said crank would be much appreciated!
vice or similar and hammer if the extractor won't engage (I've never done this but people say it works).
Some lbs have oversize thread cutters/removeers (stein) for this situation if it's worth the expense/
i have tried the hammer technique but sadly am lacking a bench and vice so it proved fairly unsuccessful - i may need to persevere with it but the baby is now asleep so can't right now!
(oh and they're not really worth the expense, though i would much rather avoid having to fork out cash as i'm very skint right now!)
I missed the earlie thread, are they square taper?
Have you def removed all washers?
I have used a hammer in the past but it doesn't do thet crank much good.
Try riding around on the bike with the bolts undone
1. no, isis.
2. yes definitely - the problem is there is visible damage to the thread going a mm or two in, meaning the extractor won't bite at all to do its work.
3. i would rather preserve the crank, the BB's for the bin anyway.
4. no can do - BB is no longer in the frame and is extra wrecked now from my efforts to detach it from crank!
Hold BB in vice and buy a new extractor (They often bite better...). Other than that an option I have seen used before is the installation of new self-extracting bolts (Again they often bite better.), and use an 8mm key to remove.
Have you tried lubricating the thread?
try rechasing the threads with a bradall/ stanley knife/ similar pointy but of metal so the tool will engage.
or try a better BB extractor? Park Tools ones seems to extract cranks that have had their threads pulled out by lesser extractors.
I can lend you one if you like.
ok, good tips. and cheers for the offer, may take you up on it depending how i get on!
What brakes said.
Otherwise if using the hammer, brace the crank on a kerb or similar - you need something that doesn't move like wooden or vinyl flooring, workbenches etc.
Apply heat to the crank arm with a hot air gun or better still, witha blow torch, best doen outside, heating aluminium allow makes a smell and sometimes fumes.
ALUMINIUM ALLOYS EXPAND FASTER THAN STEEL
REMEMBER IT WILL BE VERY HOT, SO USE THICK LEATHER GLOVES OR A HAMMER TO RELEASE THE CRANK.
Not faced the above, but have used a length of scaffolding pole and another occasion the good old angle grinder.
i've had another look, tried a bit of thread chasing with stanley knife. no luck so far... very annoying - this is becoming a costlier and costlier task!
well i concluded the crank is dead, and as there was a virtually like for like brand new chainset and bottom bracket on ebay for very cheap i bit the bullet and went for that instead!
anyone want a right hand truvativ elita crank in used but good condition?! 😆
cheers for tips all, anyway. 🙂