CRANKARM REMOVAL

frank · Post by **frank** » 20 Jun 2007, 4:59pm

Help
Whilst trying to remove the crankarm i have stripped the threads. Can anyone tell me any other way of removing them. I rode the bike around the block for 1/2 an hour but this did not loosen them . Any advice will be appreciated.

diapason · Post by **diapason** » 20 Jun 2007, 5:06pm

Sounds like a job for the LBS. If you try hitting or otherwise using a lot of force, you might end up damaging the frame

Good luck,

N

crimble · Post by **crimble** » 20 Jun 2007, 5:15pm

depending on the bike etc. you may just live with it until the last possible moment.

I would be tempted to write off the crank and BB, and:

Remove the other crank [Check the threads of your crank removing tool first, if they're at all rough or damaged get a new one. Also make sure you lock it on tight with a large spanner before starting the extraction sorry if you knew this alerady].

Saw through the BB with a hacksaw close to the crank arm.

Remove the BB as per usual.

robgul · Post by **robgul** » 20 Jun 2007, 5:29pm

See www.beewee.co.uk and the Briefings for my thoughts on the problem - the boiling water, supplemented by the wooden wedge, usually works

Rob

Asdace · Post by **Asdace** » 20 Jun 2007, 5:36pm

You could at the last resort, drill a serie of holes around the crank and weaken it. Also if you can one crank arm off and turn the frame upside down, then hit the other crank off.

frank · Post by **frank** » 20 Jun 2007, 5:54pm

I have a spare set of crankarms and a spare bottom bracket. So damaging them will not be a problem.

Post by **Mick F** » 21 Jun 2007, 5:52am

Another idea is to strip out the BB complete with the crank. Sometimes this is just possible, it depends on whether you can get both cups out whilst still having a crank on!

IF you can get it out, the job is so much more simple in a vice. Brute force and a punch and hammer will do the trick.

Other than that, a bearing puller may do it.

I seem to remember that we've discussed a siezed crank in this forum fairly recently - try a search for more ideas.

ianr1950 · Post by **ianr1950** » 21 Jun 2007, 8:06am

I soaked one with plusgas and rode the bike without the bolt in the crankarm. It eventually worked loose after about 3 hours riding.

leftpoole · Post by **leftpoole** » 21 Jun 2007, 9:06am

The answer used by Argos frame builders is, to heat the centre of the crank where it is on the taper of the bottom bracket, with a welding torch. then tap it off from behind. I would imagine a blow lamp would do the job?
John.

PW · Post by PW » 22 Jun 2007, 11:30am

The pros have 2 main methods:-
1) A steel wedge hammered in behind the crank to force it away from the B/B shell.
2) A set of automotive bearing pullers, effectively 3 hooked arms hinged onto a nut with a long bolt through the centre. You can pick these up for less than a fiver from the local fleamarket tool stall. Get two - with different length arms and interchangeable to boot. That way you can codge up a hybrid to get a grip on the chainring spider. Anything will do on the L/H crank.
If you need to heat the crank beware, keep the blowtorch on the crank centre, away from the pedal threads, the frame & the front tyre. Take the pedals off first & stop when the grease in the B/B starts to smoke :shock:

- the B/B's scrap if you do this. If the crank doesn't come off first go chuck a bucket of cold water on it. The sudden cooling helps break the stiction, then leave it while you have a cup of tea & start all over again. :cry: