Removing ancient cotter pins

[swee'pea99]

Can't shift 'em. Probably haven't been removed in 20 years or more and I just cannot get them to come out. I got the nut off (rather to my surprise, I have to admit) but even tho' the crank is loose (which is why I'm trying to remove it in the first place) I just cannot get the pin out. Been bashing it with a big hammer - so much so that I've distorted the end slightly, and will (assuming I can re-use at all) have to file the end off to get the nut back on when I'm done - but it just will not give. I've tried PlusGas, I've tried hitting it some more, don't really know what else to do. Any suggestions?

 

[Gary E]

I always used to back the nut off just a turn or so and then hit it, this prevents, or at least makes it less likely, that you'll bend the Pin. It also protects the threads so that the Pin can be re-used. On particularly stubborn Pins I'd drown it in PX24 (WD40), leave it for at least 24 hours and then use an impact wrench (lots of gentle impacts will often work better than one or two hoofing great whacks!).

You can also try putting an over-size socket over the large end of the pin (inner diameter larger than the big end of the Pin) and then use a G-Clamp (or vice if you don't mind man handling the whole bike) to extract the Pin.

Failing everything else you're looking at drilling out the old Pin

 

[swee'pea99]

Failing everything else you're looking at drilling out the old Pin

I think it might come to that. (I've tried the bench vice - no good. It's stronger than my vice, even when I hit the handle with a hammer. )

It is displaying a really quite remarkable reluctance to cooperate.

 

[Gary E]

Ahhh Cotter Pins, remember them well - not fondly though

That one looks well corroded in, good luck.

 

[ChrisEyles]

Blimey, I've struggled plenty with some myself but never had one that resisted against the bench vice.

One last thing to try is to put the vice back on (with a socket over the non-threaded end of the pin obviously), and use a cheater bar over the vice handle. If you don't have a bar, a big ring-ended spanner can also do the trick. The extra leverage might just be enough if you're lucky.

Otherwise drilling it out is the way forward. I've never had to do it with a cotter pin, but have done it a few other places, it's not as scary or difficult as I feared it might be.

In this case, getting new pins is not too hard, though I'd replace both together or the cranks might end up not perfectly at 180 degrees. I've read the new replacement pins aren't as good quality as old originals, and indeed the metal does seem a tad soft... but on the plus side that makes the easier to file down to fit properly, and since the whole idea is for the pin to sort of smoosh into place I don't think it matters a great deal. You don't need to crank down the nut, just snug it into place to stop the pin working loose, so stripping the threads shouldn't be an issue.

 

[Globalti]

How I remember those horrible things; they used to get stuck for fun.

Soaking in penetrating oil won't make a shred of difference; it can't penetrate where the metal surfaces are effectively fused together.

 

[wisdom]

Heat could be the only way I'm afraid however be careful as the grease in the bottom bracket will be no good after excessive heat.Local heat on the crank then clout the pin.

 

[Bodhbh]

[QUOTE 5020937, member: 45"]After drilling out a resistant pin a few weeks ago, I invested in a cotter pin press from the USA.[/QUOTE]

This one?

After aquiring a couple of Raleigh 20s I forked out for one. I really didn't fancy messing about with them and wanted to make it as easy as possible. Nice little tool and he also sells machined pins. How much better they are than the ones you can get off eBay for peanuts, I don't know.

 

[subaqua]

heat.

gentle tho . enough to break that nasty corrosion

 

[swee'pea99]

[QUOTE 5020937, member: 45"]After drilling out a resistant pin a few weeks ago, I invested in a cotter pin press from the USA.[/QUOTE]
How hard was the drilling? Did you use a regular (handheld) drill? (I'm not investing in a press - this is a one-off on an old bike...I don't plan to make a habit of living with cotter pins.)

heat.

gentle tho . enough to break that nasty corrosion

Heat applied how? Would a hair-drier do? (Serious question.)

 

[Gary E]

Assuming you don't have the same problem on the other side, it's possible to remove the pedal and axle together from the seized side. This'll make it about 4 million times easier to work on

 

[martin540]

I have used a scissor type balljoint separator with good results, but I don't think the pin was badly stuck. Might be worth a try though if you can borrow one?

 

[MichaelW2]

Old cotter pins are made of much better steel than new ones so it is worth preserving them.
Support the crank of a length of piper so the pin can drop out but the crank can't move.
Protect the threads with some soft metal such as aluminium block or bar punch.
With your 3rd and 4th hands strike the aluminium punch hard.

 

[swee'pea99]

Assuming you don't have the same problem on the other side, it's possible to remove the pedal and axle together from the seized side. This'll make it about 4 million times easier to work on

Amazingly I've already anticipated - I've doused t'other side in PlusGas ready for an assault!

[QUOTE 5020996, member: 45"]It's tricky, but successful. I bought a new, decent bit to do the work. Cordless drill. A centre punch is useful to stop the bit wandering. And you have to be careful with your angles. I've successfully drilled one out before and turned the axle over to find that I'd drilled into the crank. Fortunately this didn't affect things when I put the crank back on. You also need to watch that you keep the bit away from the axle. The bit will bend into the softer metal of the pin rather than cut into the crank, and you'll snap the drill.

The weirdest part is that the pin won't gradually loosen. It will either be stuck solid or free. So you'll go for ages thinking that you're not making any progress, then it will just drop away with a little tap.[/QUOTE]

Thanks - very helpful.

 

[lazybloke]

Separating ball-joints from suspension wishbones was possibly even more frustrating (if you didn't know the simple technique).

Cotter pins were a pig but never seemed too reluctant if the nut was only loosened rather than removed. That one's obviously taken a beating...