Remove Stuck Crank Arm

[MartinQ]

I've managed to strip the pedal thread from one of the crank arms, so need to put a new one on. However, getting the old one off is proving to be a problem as it won't budge (using a crank puller, oil, ...). Is the next step to drill the old crank arm and persuade it to fracture?
Thanks

 

[Rickshaw Phil]

I've had success in the past by pouring boiling water on the crank which expanded it just enough to release its grip.

 

[sight-pin]

Hi, I don't know much about bikes, but i was a diesel mechanic years ago, so have some idea about situations like this.
I would suspect that the crank arm is alloy which expands at a faster rate than steel, A gentle heating on the alloy crank arm maybe would help...Mind any paintwork though. That's how i would go about it anyway.

 

[sight-pin]

Ah!! someone beat me to it lol

 

[stephec]

What type of bb is it, square taper or something similar?

If the thread's knackered and you're not bothered about killing it try doing what I did, an angle grinder, and a large chisel and hammer.

 

[Globalti]

Got the bolt out? Just go and ride around the block a few times. It will drop off.

 

[Sharky]

Once, I had problems. I was using a crank puller to remove one of my cranks and no matter how hard I tried, it would not budge. Then I realised that I had left a washer from the crank bolt inside the crank and it was stopping the crank puller tool from working.

Keith

 

[MartinQ]

Thanks all, I'll try the boiling water trick, but I suspect that there's some corrosion which is making it stick - it's an old, badly treated commuter. Looks like partial drilling or angle grinding coupled with a bit of gentle persuasion will do the job if the gentler treatment doesn't work. Haven't used my grinder for a couple of years, will have to dig it out and see if I've any metal cutters.

 

[Nigelnaturist]

Thanks all, I'll try the boiling water trick, but I suspect that there's some corrosion which is making it stick - it's an old, badly treated commuter. Looks like partial drilling or angle grinding coupled with a bit of gentle persuasion will do the job if the gentler treatment doesn't work. Haven't used my grinder for a couple of years, will have to dig it out and see if I've any metal cutters.

Tuning fork ball joint splitter and a big hammer, it will make a bit of a mess of the crank arm though.

 

[MartinQ]

Well that grinding was good fun, off to order the new crank arm now. Thanks all.

 

[adamhearn]

Ended up doing exactly the same [removal with an angle grinder] earlier today! I was thinking of replacing the cranks and in support of that plan needed to check the BB axle length... Funny how some jobs just don't go to plan. Crankset and a replacement BB now on order