Brompton stuck folks

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Philip Benstead
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Brompton stuck folks

Postby Philip Benstead » 30 Apr 2016, 6:17pm

Brompton stuck folks

I am the third owner of a Brompton; it is 1998 vintage.
I am attempting to remove the folks
I have remove the expander bolt
I sprayed 3 in 1 penetrating oil down the bolt hole and up from the bottom of the folks.
I have tried using a screwdriver and rubber hammer hit the expander wedge from the top all round its circumference.
I have losing the headset lock nut to push the folks out
I tried pouring boiling water down the bolt hole
The wedge will not move.
I am going spray penetrating oil tonight some more and leave it overnight.
Any suggestions on how to unstick the folks gratefully received.
Philip Benstead | CTC London and FORMER CTC Councillor SE
| 0794-980-1698 | philipbenstead1@gmail.com |
Organizing events and representing cyclist in southeast since 1988
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Brucey
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Re: Brompton stuck folks

Postby Brucey » 30 Apr 2016, 6:43pm

the normal method is to back the expander bolt out a couple of turns and then to tap it with a hammer; this releases the wedge.

However if it is corroded, the wedge won't move, and if you just keep hitting it harder and harder, you will strip the thread on the bolt and this can get you well and truly stuck, with a bolt that just turns, no use for wedge releasing, can't even be removed either.

So if tapping + penetrating oil doesn't work, I'd suggest removing the bolt and then using a long drift on the top of the wedge. An old expander bolt can make a suitable drift. Be warned that you will soon burr the female thread in the wedge, but this can usually be overcome somehow once everything is apart; a wedge from another stem if needs be.

NB steerer tubes are usually internally butted; often a wedge will move a short distance inside a short steerer and then jam against the butt. If the stem is corroded in position and won't move even when the wedge is free, it is easy to assume that the wedge isn't really free, and that is why the handlebars are not moving.

Of course the wedge may indeed not be 'free' per se, it can be comprehensively jammed into the taper on the steerer butt.... :roll: but if so, it isn't what is stopping the handlebars from coming out....

If you are really unlucky the wedge was always hard up against the butt and would thus inevitably be a real handful to release, even if the parts are not in any way corroded.

cheers
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rjb
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Re: Brompton stuck folks

Postby rjb » 30 Apr 2016, 9:15pm

My Dawes Kingpin small wheel folder had a retention strap attached to the base of the stem which was retained by the brake front brake caliper attachment bolt. To remove the stem required the front brake to be removed first. I have no idea if the Brompton uses a similar arrangement, but if you inspect the brake caliper bolt and see a wire strap it may be similar. Best of luck.
At the last count:- Focus Variado, Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin, Raleigh 20, Falcon K2 MTB dropped bar tourer, Longstaff trike conversion on a Falcon corsa. :D

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Philip Benstead
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Re: Brompton stuck folks

Postby Philip Benstead » 1 May 2016, 11:31am

Got them out , left overnight with penetrating oil, but that was not the problem. The wedge had ridges on it sides. My solution was to insert a longer expander bolt with packages pieces on the bottom , i did it up as tight as I could it still required lots of bashing , but it came out as I then bash from the top. It came free folks remove but wedge moved 180deg I then bash it out , I will replace the wedge when possible.
Philip Benstead | CTC London and FORMER CTC Councillor SE
| 0794-980-1698 | philipbenstead1@gmail.com |
Organizing events and representing cyclist in southeast since 1988
Cycle Ride? http://www.meetup.com/socialcycling4u/
Bikeability Instructor/Mechanic

Philip134
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Joined: 4 Jan 2020, 12:04pm

Re: Brompton stuck folks

Postby Philip134 » 4 Jan 2020, 12:08pm

Releasing a stuck Brompton Stem – a solution!!
• Loosen the stem bolt by using an allen key to undo the bolt by 4 or 5 turns
• Cover the bolt head with a piece of wood and whack it hard to drive the bolt down and release the wedge from the bottom of the stem.
• Remove the front wheel, the front mudguard and the front brake assembly. Let them hang loose without stretching the brake or lighting cables. Secure with PVC tape if necessary.
• Unscrew the bolt and remove. (This is not required if the stem rotates and can be removed in the normal way).
• Using a long screwdriver or a suitable drift, drive the wedge out of the bottom of the header tube. The wedge will be a tight fit at the bottom of the tube and you will need to drive it slowly.
• Secure the bike upside down, say in a Workmate or similar.
• Now you need a socket that is a tight fit to the inside of the bottom of the header tube. The best choice seems to be a 16mm plug socket. A standard (shorter) socket will do but the added length of the plug socket seems to help. If you don’t have metric sockets, 5/8” imperial sockets are good as well. (See Photo)
• Now insert a 150mm (6”) extension bar on to the socket.
• Snug the socket into the bottom of the header tube and allow it to rest on the bottom of the stem. A few goes with penetrating oil on to the bottom of the stem before this will be helpful.
• With the extension bar protruding out of the bottom of the header tube, give the end of the bar some sharp whacks with a standard claw hammer.
• Surprisingly the stem will start to move after a few whacks. As the stem emerges it will drop down at increasing speed. Take care as you get to the end of the stem otherwise you will end up driving the socket into the end of the stem.
• Remove everything and clean up.
• Use a 36mm spanner to remove the headset, clean and grease.
• Reassemble, grease the stem tube before reinserting it. You will probably need a few hammer taps on a wooden block to reinsert the stem.
• Reassemble brake, mudguard and wheel.
Image Attachments
Brompton.jpg
Last edited by Philip134 on 14 Jan 2020, 1:06pm, edited 1 time in total.

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Gattonero
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Re: Brompton stuck folks

Postby Gattonero » 7 Jan 2020, 8:42am

FWIW, Brompton stems are held in the foRks with a tapered "cone", not a "wedge", if you try to push it from the bottom of the forks it will only get more stuck.

For a start, this bike may be with the older 1" stem/forks, for which parts are not available anymore, so put extra-effort only if the parts are already on hand.
Then, since the Brompton will have mudguards, it's most likely that rain/moisture leaked down from the top (by the bolt head in the stem hinge) so I will look and work from there. Last chance is to remove wheel and mudguard and stem bolt, and using a torch needs to heat up the forks then using a longer stem bolt and try to move the stem cone further down, then up again by fitting the bolt backwards.

Past this, hey, someone said that quill stems were the best thing since slice bread? :wink:
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

Brucey
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Re: Brompton stuck folks

Postby Brucey » 7 Jan 2020, 9:24am

Gattonero wrote:FWIW, Brompton stems are held in the foRks with a tapered "cone", not a "wedge"....


both types are used in Bromptons, depending on the age of the bike.

Bromptons have the advantage that they are not often left out in the weather. They also have the (not inconsiderable) disadvantage that there is usually little or no grease on the parts when they leave the factory.

cheers
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Gattonero
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Re: Brompton stuck folks

Postby Gattonero » 7 Jan 2020, 2:12pm

Brucey wrote:...They also have the (not inconsiderable) disadvantage that there is usually little or no grease on the parts when they leave the factory.

cheers


Your opinion not supported by facts.
If you had been in the factory you would know that Castrol Sphenol LMM everywhere.
That is simply seized with age, a problem that happens with the quill stem design (and like many other tight-fit parts).
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

Brucey
Posts: 37299
Joined: 4 Jan 2012, 6:25pm

Re: Brompton stuck folks

Postby Brucey » 7 Jan 2020, 5:48pm

Gattonero wrote:If you had been in the factory you would know that Castrol Sphenol LMM everywhere.
.


There is no such thing as Castrol Sphenol. Presumably you mean Castrol Spheerol.

They may well have had pots of grease in the factory when you visited; it of course in no way assures that they were and always have been applying it appropriately. Most of the Bromptons I have dealt with that were built in the noughties were notable for their lack of grease (on anything).

cheers
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foxyrider
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Re: Brompton stuck folks

Postby foxyrider » 7 Jan 2020, 9:09pm

Brucey wrote:
Gattonero wrote:If you had been in the factory you would know that Castrol Sphenol LMM everywhere.
.


There is no such thing as Castrol Sphenol. Presumably you mean Castrol Spheerol.

They may well have had pots of grease in the factory when you visited; it of course in no way assures that they were and always have been applying it appropriately. Most of the Bromptons I have dealt with that were built in the noughties were notable for their lack of grease (on anything).

cheers


+1 cleanest bikes on delivery you will ever see! :lol:
Convention? what's that then?
Airnimal Chameleon touring, Orbit Pro hack, Orbit Photon audax, Focus Mares AX tour, Peugeot Carbon sportive, Owen Blower vintage race - all running Tulio's finest!

Brucey
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Re: Brompton stuck folks

Postby Brucey » 8 Jan 2020, 12:04am

foxyrider wrote:
+1 cleanest bikes on delivery you will ever see! :lol:


I have always wondered if this is deliberate, i.e. so that there is no chance of folk getting smuts of grease on their clothing. The easiest way of making sure there is no grease on the bike to come off is not to put it on in the first place.... :roll:

cheers
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Gattonero
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Re: Brompton stuck folks

Postby Gattonero » 8 Jan 2020, 8:12am

Brucey wrote:
Gattonero wrote:If you had been in the factory you would know that Castrol Sphenol LMM everywhere.
.


There is no such thing as Castrol Sphenol. Presumably you mean Castrol Spheerol.

They may well have had pots of grease in the factory when you visited; it of course in no way assures that they were and always have been applying it appropriately. Most of the Bromptons I have dealt with that were built in the noughties were notable for their lack of grease (on anything).

cheers


Nitpicking at its best (and why am I not surprised?)
You can change two letter but those are the pots.
Image

Truth is, if you had to put together and fix a few hundred bikes a year, just as I've done, it will prove you just wrong.
You may have seen one or two bikes at random times, so your data is a couple of units out of half a million, 'nuff said!
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

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Gattonero
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Re: Brompton stuck folks

Postby Gattonero » 8 Jan 2020, 8:14am

foxyrider wrote:
Brucey wrote:
Gattonero wrote:If you had been in the factory you would know that Castrol Sphenol LMM everywhere.
.


There is no such thing as Castrol Sphenol. Presumably you mean Castrol Spheerol.

They may well have had pots of grease in the factory when you visited; it of course in no way assures that they were and always have been applying it appropriately. Most of the Bromptons I have dealt with that were built in the noughties were notable for their lack of grease (on anything).

cheers


+1 cleanest bikes on delivery you will ever see! :lol:


As above: how many Bromtons have you ever seen like that, have you actually take them apart (provided you actually know how to do it, and to put the bike back together properly) in the headset, BB, both pedals, stem, and the likes? You may have done once, some people does it once evey hour... :wink:
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

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foxyrider
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Location: Sheffield, South Yorkshire

Re: Brompton stuck folks

Postby foxyrider » 8 Jan 2020, 10:05pm

Gattonero wrote:
foxyrider wrote:
Brucey wrote:
There is no such thing as Castrol Sphenol. Presumably you mean Castrol Spheerol.

They may well have had pots of grease in the factory when you visited; it of course in no way assures that they were and always have been applying it appropriately. Most of the Bromptons I have dealt with that were built in the noughties were notable for their lack of grease (on anything).

cheers


+1 cleanest bikes on delivery you will ever see! :lol:


As above: how many Bromtons have you ever seen like that, have you actually take them apart (provided you actually know how to do it, and to put the bike back together properly) in the headset, BB, both pedals, stem, and the likes? You may have done once, some people does it once evey hour... :wink:


i worked in bike shops for best bit of 30 years and latterly in the Brompton main agent - i got to unwrap just about every one that passed through the store so i do have a little bit of experience.
Convention? what's that then?
Airnimal Chameleon touring, Orbit Pro hack, Orbit Photon audax, Focus Mares AX tour, Peugeot Carbon sportive, Owen Blower vintage race - all running Tulio's finest!