Stripped thread Crank Removal - Car Jack

[stu76]

Just a little tip for anyone struggling to remove a crank arm with stripped threads.....

I had a set of cranks I wanted to remove from a frame but the non-drive side threads were stripped. I tried all the usual techniques, blow torch, big hammer etc etc, but still wouldn't budge. So.....

I bolted the drive side crank arm back on to the BB in the same direction as the non-drive side (i.e. both pointing the same way) and put my car jack between the two inner crank arms. A few turns of the handle and the stuck crank arm popped off. Job done!

A few words of caution- Try this at your own risk - I did this on some rubbish cranks, I just wanted to harvest the BB from the frame. I'd probably use a more sensitive technique if they were a decent set or get an LBS to do it. Also I would probably turn the jack handle a few times then back it off a bit, then re-turn, gradually building the pressure until it comes of. This might help save the crank arm from bending or damaging the BB.

 

[Barneyballbags]

Great tip!

If only I knew that before taking a hacksaw to my old LX cranks

 

[Pierre]

Good tip! I'd try and take the chainrings off and move the jack closer to the BB shell if possible, so that the brute force is more in the direction needed to pull the cranks off (rather than bend them on the axle, if you see what I mean), but great idea, haven't seen that before.

 

[lewis1641]

I would be inclined to loosen the bolts but leave them in if I were doing this.

But I am not an engineer

 

[02gf74]

a long bolt through the holes for the pedals to keep the cranks from bending may be an :idea:

 

[jax13]

a good bodge!

my worry would be that if the jack is too far down the pedal arms there could be a small chance of bending the axle or bending a crank arm as already said.

in the same way as seatpost removals etc. you do it at your own risk as there is never a 100% certain way of removing extremely well stuck components.

 

[elPedro666]

a long bolt through the holes for the pedals to keep the cranks from bending may be an :idea:

And a good bodge becomes a great solution, cheers both for sharing - see how much better we are together? *






* I have no idea where that schmoltz came from :? Good tip though!

 

[kampos]

Another method I've found useful on occasion is a car hub puller -- they tend to come in 3- or 5- arm flavours ; as long as you can find some purchase then it works ; clearly better for drive side though.

 

[stu76]

I think the additional refinements mentioned above should make this a pretty robust method. The power of the collective mind eh.

 

[dvatcmark]

+1 for the car hub puller method, I've used a 3 arm puller a few times to remove stripped cranks.