[Closed] Removing a REALLY stuck Square taper crank - HTF

Gear Puller.

[img] https://media.screwfix.com/is/image//ae235?src=ae235/12510_P&$prodImageMedium$ [/img]

Ball joint splitter plus heat - not the forked hammer type but the type with a screw thread
https://www.amazon.co.uk/Draper-13914-Capacity-Joint-Separator/dp/B0001K9PKU?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-brave-uk-21&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B0001K9PKU

I have a cold chisel of the right thickness/angle to fit between BB cup and crank arm and a 4lb club hammer.

In bike shop, angle grinder to cut 2 slots in end of arm - assuming its scrap

Ball joint splitter plus heat – not the forked hammer type

The forked hammer type absolutely does the job too, plus you get to hit stuff

with the cold chisel am i going in perpendicular to the crank? if so thats how ive used the ball joint splitter to no avail
angle grinder had a new disc when i started but not cutting great. What discs are best to cut into the metal?

If you're using an angle grinder buy a thin, metal cutting disc (rather than a grinding disc) and wear eye protection.

Can you get some penetrating oil on the frame side of the taper? Have you tried putting the other crank back on and taking it for a careful ride so that pedalling forces loosen it?

Aluminium expands more than steel so that should be very helpful in loosening it too.

Are you turning it the right way?
Over the top to the front.

You also want a socket holder and a breaker bar (I use a Trailgator - only thing it is good for)

https://pedros.com/products/tools/pedal-crank-and-bottom-bracket/bb-socket-holder/

there is no thread left - it pulled out - the cranks been on for >20 years

click for the horror show

If you are not managing to cut through an alloy crank with a grinder, have you made the mistake of accidentally using a child's Bob The Builder grinder?

Cut a slot along the axis of the axle, whack a chisel into the slot, and the crank will pop right off (if it hasn't already with just the slot cutting)

Edit: just seen the picture. Jebus. Use a cutting disc. Lop the spider arms off first if access is tricky.
Also give it some taps towards and away from the frame to try and lever it off.

alloy or alu?

Hacksaw worked a treat on mine, 2 slots 10mm apart as near to the axel as poss then drive out the bit in the middle with a hammer and chisel...

Looks to me like it's still held onto the axle with the bolt:

So ain't no pulling getting that off!

Cut the spindle.

Hope the BB isn't seized.

They are a real pig if dry assembled.

Hateful design. I love outboard bearings for this reason.

Bon chance.

Cut the spindle.

This. Get a decent full-size hacksaw and a sharp new blade. Cut it off behind the chainset. Then go for the BB with penatrating oil 😀

I'd probably remove rings and what else I could to improve access. Then clamp the spider to a tube with a toestrap or (modern) big zip tie).

Cut the spindle

I think he was asking what will cut it.

dezb - DEFFO no bolt in there buddy!! That is what is left of the axle!!

Hacksaw is not touching it with a new blade in!!

Then [p]ray for the BB

See, this is the thing - you go through all this and find that you can't get the BB out of the frame anyway. So have to trash the frame. Been there, done that.
The splines on an old BB just aren't grippy enough to remove a seized one.

I'm betting this is a job you offered to do for a friend 😆

Hacksaw won't cut it.

As mentioned a spanking new metal cutting disc in a grinder right through your spindle, after you've cut the rings away with same.

ONly positive is that the NDS cup came out easily as was plastic. SO at least penetrating oil/plusgas MAY get into the drive side threads?

DEFFO no bolt in there buddy!! That is what is left of the axle!!

Oh wow. Maybe it'd pull off then! I stand by what I said about the BB though 😀

like this?
https://www.screwfix.com/p/norton-metal-cutting-disc-5-125mm-x-1-6-x-22-23mm/8301v

Use to go for a ride sans bolts to get cranks loosened off but that door is closed given the chopped chainrings

Hacksaw should go through the axle. Had an octalink BB off that way before.

Looking at that pic I'd just get an angle grinder on that now and stop faffing about with a hacksaw!

Chop it up and sell as 'mint' on eBay! 🙂

Will someone please link to a suitable cutting disc that is 22.2 diameter

I'm guessing you've got a standard 4.5" grinder? If so, https://www.screwfix.com/p/metal-cutting-disc-4-115mm-x-1-x-22-2mm-5-pack/2585v

Bur please please please also wear at the very least goggles and gloves. Better still a visor. Cutting discs can be relatively easy to snap, and when they do, can cause a lot of damage.

See, this is the thing – you go through all this and find that you can’t get the BB out of the frame anyway. So have to trash the frame. Been there, done that.

I’ve restored countless old bikes and never been beaten by a crank or bottom bracket. The biggest tip is to only break out the hacksaw or grinder when all other engineering solutions have failed.

I once removed a cup and cone BB out of a 25 year old bike which had been sitting outside for several years. This needed a 36mm (IIRC might have been a 32mm) headset spanner on the flats to remove the fixed cup on the drive side. It kept slipping off so I clamped the spanner to the cup using threaded bar and some huge washers and metal plates. Then with a 1m long extension on the spanner it eventually cracked off. Took a while to unwind it from there but the crack was the rust bond separating.

The best way to remove sq taper cranks is to ride them around without the bolts on - soon comes off!

I had a similar problem with a campy bb.
My mate welded a long bar to it and it wound out easily.

Let's hope he knows if it's Italian or English thread.. 😉

I'm reminded of this 🙂

https://singletrackmag.com/forum/topic/removing-cranks-from-a-square-taper-bb/

Let’s hope he knows if it’s Italian or English thread.. 😉

Shouldn't matter (I think?) the cartridge side is always the same, just the spacer is different?

I removed one no problem with an angle grinder, just metal discs from B&Q or those that came with it (lidl special) I think.

Just cut down level with one face of the sq taper. Try not to cut al. and steel with the same disc as it can cause fire (probably not an issue in a home workshop but if you had a load of swarf from other stuff it could be.) - think thermite reaction.

It looks like you've been grinding all over the place, not keeping it focussed on making one cut that will do the job.

In terms of the BB, hopefully its steel shell/steel frame, or alu shell/alu frame, then it should come out without much bother. You can clamp the BB tool in the vice and rotate the frame around it which gives you a lot of torque - and soak in plusgas for a while first to make it as easy as possible before you break any tools or fittings for tools.

swedishmetal

The best way to remove sq taper cranks is to ride them around without the bolts on – soon comes off!

This. Maybe pad your toptube. 🙂

Too late now though.

Amazing how many people don't know this.

Looks a mess. I’ve not had this before but I’d cut away as much of the spider arms holding the chainring on as possible to give you better access to the metal round the bb spindle. You should then be able to cut downwards on it and get it split in half.

I’m assuming if it’s a small grinder it’ll be 4.5” - some cutting discs from b & q will do the job.

I echo the safety gear comments - definitely wear goggles at the minimum.

When it comes to the bb I’d soak it with penetrating oil for a few days before having a go at it. The last one I had wasn’t moving dry, but having sprayed it numerous times with penetrating oil over a few days it then cracked off ok. Replaced with gxp external bearing bb!

I had this issue with the boy's bike, handily the old crank was aluminium so a hacksaw went through it with easy, after that a chisel to crack it past the BB spindle and it was off.

Square tapers are evil.

As an alternative, if the NDS is out I would be tempted to try using a punch/chisel on the axle, driving it into the shell, supporting the crank on the outside of the shell.

When you eventually get to the nds cup / bb removal use a big g-clamp to hold the splined tool firmly in place so it doesn't slip off / mash the splines.

I really can't believe someone suggested cutting through a hardened steel axle with a hacksaw.....

It’s off
BFO mallet

Good man, well done.

Bb came out so easily too. New one in and cranks on. Anti seize applied

Victory!

Glad it's out but you should have gone for outboard bearings.

Square taper and that horrid toothed interface for the BB can >>>>>>>>>>>

Nice colour frame, what is it?

Happy to be wrong! 😀

Well my hack saw went through a hardened steel Abus D lock shackle just fine, an axle is not so different. Took a new blade. But when your son has lost the spare key as well as the main, you’d be surprised what you can do with a big vise and a bit of effort. Next step would have been a portable angle grinder, but I thought I’d spare the investment.

A good quality bi-metal hacksaw blade will cut hardened steel, although it'll take a bit of work to do.

A really old steel dawes flat bar 700c bike

bb removal use a big g-clamp to hold the splined tool firmly in place so it doesn’t slip off / mash the splines.

I always just put the crank bolt back on the BB to hold the tool on.

The bb was NOT the issue - it was the CRANK ARM

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