Hinge pin on a Brompton

anyone have any idea on how to get the pin out of the hinge on a Brompton?

i was thinking a punch on the underneath of the pin and giving it a wallop but have read somethings about a special tool. is there a 'way' of doing this?

this is the pin i am on about

When I did it, I drilled out one end of the pin with a drill bit a bit smaller diameter than the pin (this was to thin down the metal in the expanded portion of the pin).

I then cut off the drill bit flutes with a grinder and used the shank and a clamp to force the pin out.

There may be an easier way, but that's what my cat told me to do and it turned out fine.

nice one thanks.

so drill one end and press out the other?

Is that work.....

It was a pleasure.

yeah worked for me, drilled it out and pressed the pin out with a vice. pressed a new one in easily enough

The official way is, drill the top section off thats split open, then remove that with the specific tool. ream the hinge, insert new pin with said tool, split the top so its locked in

Hi all (that have removed and replaced their hinge pins)...

Where did you get a replacement pin? What’s its size?
How did you flange the new pin once in place? Is there a special tool for that, and if so what is it called?

Thanks

They do various sizes as they figure that the hole in the frame may become enlarged through wear. If you're just replacing yours for fun, get the smallest one. If your hinge was wobbling, maybe a larger one is required. You can definitely get them from a brompton dealer.

Thanks for the info.
Apparently you can’t but them without having them fitted by a licensed mechanic/dealer. Damn it!!

Makes sense I suppose. It’s a pretty critical piece of the bike. Wouldn’t want to fit it badly myself then the frame falls apart when I’m doing 30mph down some sweet hills!

Anyway, thanks for the advice.

you can get them, https://www.evanscycles.com/brompton-hinge-spindle-main-frame-lwb-6-00mm-EV301230?lsft=esvt:59748-GOUKE4844156,esvq:,esvadt:999999-0-1324678-1,esvcrea:237693822154,esvplace:,esvd:c,esvtg:pla-420048739844,esvo:EV301230-NA-SVR,esvaid:50080&esvt=59748-GOUKE4844156&esvq=&esvadt=999999-0-1324678-1&esvcrea=237693822154&esvplace=&esvd=c&esvtg=pla-420048739844&esvo=EV301230-NA-SVR&esvaid=50080&gclid=EAIaIQobChMIo5eEoq7R2wIVBN-yCh2pFAXdEAYYAiABEgLLYvD_BwE

to flange the pin you just give it a wack with something to flare it out. theres no special tool needed. you just need it to flare to stop from falling out. figure out it's mechanical purpose then work to that. its not a Brompton specific anything, its just a hella basic metal hinge.

I think when I did it I used the corner of a chisel a couple of times to get an even flare then pressed something in to it to flare it out evenly all round.

That’s odd. I’ve spoken to several people (including Evans) who won’t sell the pins to me without fitting them themselves. Apparently it’s a condition of being a Brompton dealer... I’ll try buying a couple from that link. Thanks!

That is correct, plus, you need to ream out the frame correctly and there is a specific tool for fitting / removable. Just twating a pin in there will result in the frame wearing.

Managed to buy some from Evans... although I hope I’ve got the correct size. Guess I can return if not.

Any idea what size reamer to use? I understand what reaming is and how to do it, but not sure how to select the correct size for this specific hinge pin. The pins that I removed are 6.05mm and 6.14mm at the main part of the shaft, so I’ve ordered a 6.0mm and a 6.1mm from Evans. Obviously the reamed section needs to be wider to allow for the flanging to get a grip. (Are these the correct terms?... I’m just part time mechanic of cycles)

I understand both points of view. On one hand it’s a very simple and non-specific, hinge based task. While on the other I could find myself with a badly connected hinge that causes a fatal accident.

I will not be “twating” it in :-)
I’m working on a home improvised press type tool, along with various combinations of things I’ve read about on the deepest, darkest web. (This info about Brompton hinge pins is not readily available... they don’t want us to know how to do it... totally understandably!!)

it's the same basis as a car door hinge, you may be able to find one of those door hinge tools easier than the Brompton one. and the info on doing the job should be readily found too.

so long as everything fits cleanly on all edges of the pin and there's no play, you should be good to go.

if you fit it and find there is play then you need to start again until it's right.

I would agree you can remove and fit the pin quite easily at home as already described, the main problem will be reaming to remove the play/corrosion. you'll find it hard to get 6.1 and 6.35 hand reamers (don't use machine reamers) to do this part anywhere near the cost a Brompton dealer will do it for. The only time you won't need to ream is if its barely used but got a bit stiff - remove, clean and replace with the same size or if you don't care about your hinge working loose and falling apart!

Thank you, Dogtemple and 91010.
It’s slowly becoming clearer.

There’s nowhere local (Norwich) who has the tool to carry out the hinge insertion. So I would have to send it off (£20 postage at a guess) plus parts and fitting (£40 apparently).

To do the work myself will cost slightly less, and I’ll be slightly more knowledgeable in the world of flanged hinge pins! I am a patient and logical, mechanically minded/experienced person, so I’m not going to rush this and do it badly. That’s why I’m gathering all the info I can before attempting anything. And anyway, I have a week before it comes back from the powder coating shop... plenty of time to prepare!

I’m imagining a G Clamp and a ballbearing (of a size very slightly larger than the eventual flange opening) to squash the flanged part evenly into place. Obviously this is going to be a homemade, one-off setup, so my invented tool doesn’t need to be super convenient to use.

Is there not an Evans in Norwich? I know they're best avoided but should actually have the reamers and tools!

HAhaha... you’re very funny. ;-)...
Evans don’t have the hinge tool, but do sell the pins. Which, according to Brompton, they’re not allowed to sell unless fitted in store. It’s a “supply and fit” part, which I’ve ordered from their website. (Shhhh)

tbf, the mechanics and staff at Evans in Norwich have been really very helpful. I can’t speak for their mechanical work, but the customer service (considering I hadn’t bought anything in relation to this hinge) has been great! They seem to think that of their London shops has the tool...
I guess it’s just not necessary to equip all stores with a specific tool that might not see a lot of use.

They will have reamers for other jobs I’m sure, but I like the idea of having the tools myself. There’s been a few occasions over the years when the ability to ream bike stuff and metal work would have been handy.

Looks like 6.35mm hand reamers are available cheap (probably because that's quarter-inch), but 6.1mm aren't.

only if they are premier dealers, many are only authorised or recommended to sell bikes and not service them

Yeah good point.
I have a feeling it’ll need to be more like 6.8-7.0mm I need for the flanged section. That’s what the current, non- ruined end of the pins I’ve taken out measures with a digital vernier.

do you want me to upload the official info / document?

Not sure what you mean, but yes please!

there you go

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