Pulling a stiff crank

eteb · Post by **eteb** » 16 Apr 2007, 7:56pm

First post - hello y'all!

Just wondering if anyone can help me with a v. stiff crank that won't pull. It's on a CB Majestic that my brother kindly left in the rain for several weeks.

I've got myself a Bikehut crankpuller. The left crank has come off okay, that was replaced c. 50 miles back so no worries there. There was some creaking for c. 2 turns of the puller and then it came off no probs.

The right side is a different story - I tighten it right down, there's a cacophony of creaking and popping, and then it gets too tough for me and my 6in spanner.

I'm chary of tightening it too much in case I bust something - can anyone give any advice? Many thanks.

hubgearfreak · Post by **hubgearfreak** » 16 Apr 2007, 8:05pm

when i had this trouble, i used one of these

4th from bottom

http://www.silverlinetools.com/index.html?code=MS23

you may have a friend who likes to repair his (or her) own cars?
or maybe you know a friendly mechanics?

reohn2 · Post by **reohn2** » 16 Apr 2007, 9:23pm

Try this,lie the bike on the side the crank's on then lots of eze it oil or WD40's between crank and BB spindle from the frame side,let it soak a bit then try it again.

robgul · Post by **robgul** » 16 Apr 2007, 9:49pm

Get the crank puller connected up and ready to wind - then (with the bike outside and leaning against a wall) pour near to boiling water from a kettle over the "meat" of the crank arm where it is on the BB axle. The heat will expand the alloy of the crank at a rate slightly faster than the steel BB axle - whilst still hot turn the puller.

OR fashion a couple of bits of wood into thin wedges and gently force them between the crank arm and the face of the BB either side of the axle - tap evenly with a hammer. The hot water also helps here.

OR do the same as the wooden wedge thing but use a thin cold chisel.

Usual Blue Peter caveats on boiling water etc.

Rob

Kentish Man · Post by **Kentish Man** » 16 Apr 2007, 11:15pm

reohn2 wrote:Try this,lie the bike on the side the crank's on then lots of eze it oil or WD40's between crank and BB spindle from the frame side,let it soak a bit then try it again.

And if it doesn't work immediately, don't release the extractor - just leave it over night. It's a trick my father showed me years ago for removing tapered shafts e.g. on car king pins: it may work for you.

Post by **Mick F** » 17 Apr 2007, 8:46am

As you can get one crank off, can you not un-do the BB and get the offinding bit off the bike?

That's what I'd do, then get it into a "workshop environment". Use a vice and decent tools to do the job. Be careful to make sure that the crank puller is screwed into the crank as far as it will go, so you use all the threads to pull with.

As alu has a greater co-efficient of heat expansion the steel, a good trick is to put the thing into a LOW oven. I've done that in my Mini modifying days. (I had a 100bhp 1400cc - went like a rocket!) The Drop Gear housing is alu, and getting the bearings out is a bugger. The oven idea works, I can assure you!

The "wedge" idea is a last resort, but at least in a vice, you'll get some good purchase and a solid point of work. Penetrating oil will work eventually given enough time. A gentle blowlamping may work too, to expand the crank.

The trouble is, if it's stuck fast, and you eventually release the crank, you may have damaged something, or at least spoiled the cosmetic look.

If you can get it out of the bike, but not get the crank off, consider a new BB and crankset. Some are quite reasonably priced.

Please get back to the Forum to keep everyone updated, we are on tenderhooks to find out how you get on!

diapason · Post by **diapason** » 17 Apr 2007, 9:09am

I hads a similar problem a while back on a Scott hybrid I rescued from a skip for my daughter. After trying everything, I took it to the LBS on the basis that if they broke it, they would replace it :evil:

When I picked it up, they told me that it had taken three blokes to get he crank off: two to heave and one to stand on the frame!

Good luck,

N

eteb · Post by **eteb** » 17 Apr 2007, 9:20am

Quick cheeky post from work, to say thanks for all the advice. I'm off to buy penetrating oil tonight, and I'll let you all know how I get on with the various ideas!

Next opportunity to work on it is Thursday eve, so I'll get back on the board after. Cheers for all the ideas, guys.

Edward

PW · Post by PW » 17 Apr 2007, 10:35am

I keep a selection of automotive bearing pullers in case a crank thread strips. Different sizes with interchangeable arms are useful, they allow the construction of a hybrid tool to get a good grip on the chainring spider. If it's really stubborn, and if you don't care about the B/B unit, then whip off the pedals & if possible the chainrings. Then warm the centre of the crank with a blowtorch. Stop when you see smoke coming from the B/B & be very careful to keep the flame off the frame, tyres & the pedal hole at the end of the crank. If it still won't give chuck a bucket of icewater over the still warm crank. Rapid expansion/contraction helps break the stiction. - And next time grease the axle!

Post by Si » 17 Apr 2007, 10:57am

I've tried most of the suggestions given and over time I've come to the conclusion that if a crank is difficult to get off because it is at all misshapen then there's a good chance that you won't want to put it back on again because it'll be just as hard to get it to stay on without over tightening it and getting it stuck on again. Thus, in this case, I just use a hack saw on modernish cranks - can whack through one in next to no time, then bin it and the BB and replace with new ones.

Gear and ball joint pullers can help but won't fit all crank types so borrow one rather than investing in one.

The other method that I find works 99.9% of the time is to just undo the crank bolt, put the bike in a high gear and ride up an 'ossin steep hill. Best to wear shin pads though :wink:

PW · Post by PW » 17 Apr 2007, 11:06am

Bearing pullers only cost £3-75 a throw off the flea market! That's £1-30 cheaper than 5 years ago. :wink:

And the hooks can be "modified" with a coarse sanding disc in the electric drill! :roll:

eteb · Post by **eteb** » 18 Apr 2007, 10:03pm

Thanks for all the advice, guys. It came off tonight with a combination of 3-in-1 Professional Penetrating Spray from Halfords, left for several hours, then one person holding the bike and me more or less hanging off the spanner.

The force of the puller seems to have cracked the outermost thread on the BB spindle - esp since it was being turned under such pressure I guess, and I don't know without fitting them whether the new cranks will be happy without it.

But at any rate the **** thing's off, and the bike can go to Vaz for a rebraze and respray as planned.

Thanks for all the very ingenious suggestions - sorry I can't report back I tried each in turn! Will all be v. useful for next time I lend the bike out...

Edward

hubgearfreak · Post by **hubgearfreak** » 18 Apr 2007, 11:44pm

eteb wrote:The force of the puller seems to have cracked the outermost thread on the BB spindle - esp since it was being turned under such pressure I guess, and I don't know without fitting them whether the new cranks will be happy without it.

tell me that you're fitting new BB with your new cranks, please?

eteb · Post by **eteb** » 19 Apr 2007, 7:32am

Sounds like it then! Total newbie to doing this sort of maintenance, and I'm doing this bike up (see above, more or less trashed by bro) so I can learn the ropes. If you can recommend a decent book to help, would be great - I've got Richard Ballantyne's, and some native nous...

eteb wrote:I don't know without fitting them whether the new cranks will be happy without it.

... Or so I like to think! I'm having trouble with the nitty gritty and the unexpected.

I assume you mean I should have a new BB on account of the spindle? Thanks for the tip!

Kentish Man · Post by **Kentish Man** » 19 Apr 2007, 12:36pm

eteb wrote:The force of the puller seems to have cracked the outermost thread on the BB spindle - esp since it was being turned under such pressure I guess, and I don't know without fitting them whether the new cranks will be happy without it.

Would it help to place a penny or 2p coin between the extractor and the axle, to act as a soft metal cushion? Anyone have any views on this?