Forks stuck fast

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Frattoniser
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Joined: 4 Jan 2014, 9:41am

Forks stuck fast

Postby Frattoniser » 25 Aug 2014, 10:41am

Hallo, I have a classic 'Rotrax' frame (1953), but I can't remove the forks from the stem/stearer. I've used WD40, vinegar etc but its a no go. Any ideas before I consign what is a beautiful frame to the skip?

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gaz
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Location: Kent, lorry park of England

Re: Forks stuck fast

Postby gaz » 25 Aug 2014, 11:11am

Assuming steel forks and alloy stem the "chemical" solutions in the stuck seatpost thread may help : viewtopic.php?f=5&t=16716
There'll be tarmac over, the white cliffs of Dover ...

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Mick F
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Re: Forks stuck fast

Postby Mick F » 25 Aug 2014, 11:22am

Assuming a quill stem and assuming you are happy to cut it off ..........

Cut the stem above the headset, and remove the headset to allow the forks to come away from the frame. At this point, you can get the stump of the stem very tightly into a bench vice held vertically. You may then be able to turn the forks, but do not use the dropouts to twist the forks, but find a longish stout piece of wood to rest in the fork crown and use that as a "tommy bar".
Mick F. Cornwall

PT1029
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Joined: 16 Apr 2012, 9:20pm

Re: Forks stuck fast

Postby PT1029 » 25 Aug 2014, 11:54am

Suggest a modified Mick F solution.
Try the twisting method before cutting the stem off. Put the forward extension part of the stem in a robustly mounted vice. Try the twisting with a big piece of wood as suggested, but ensure you put a front wheel (or hub) in the forks, otherwise the fork blades are very liable to bend/twist. They will probably get a dent on the inside of the blade from the wood, probably not structural. They may twist anyway (I suppose you could twist them back.....?)
If you are able to rotate/twist the forks, you may need a sturdily built assistant to push the bike frame upwards as you twist the forks.
If you want to soak it some more, Plus Gas is alot better than blue can WD40 for unsiezing. WD 40 infact do a range of degreasers/cleaners/penetrants. The orange can WD 40 is pretty good for this. Coke Cola isn't bad either. I have found the orange Wd 40 and Plus Gas in Halfords. If you have the time, soak/keep applying for weeks first.
I once knew someone who soaked a 1930's BB shell for 2 years in coke before the cups came out!

DeepdalePete
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Joined: 29 Jun 2013, 10:18pm

Re: Forks stuck fast

Postby DeepdalePete » 27 Aug 2014, 9:50pm

PT1029 is spot on with the plusgas. By far the best thing you can use to sort this out. You'll need quite a bit but it can be re-used. Hang the frame so that the forks and the headset are immersed in the solution. Leave for at least a week before you try to loosen them. Buy the 5 litre one if I were you. WD40 is best used as a cleaner and water repellent.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Forks stuck fast

Postby Brucey » 27 Aug 2014, 10:33pm

Frattoniser wrote:Hallo, I have a classic 'Rotrax' frame (1953), but I can't remove the forks from the stem/stearer. I've used WD40, vinegar etc but its a no go. Any ideas before I consign what is a beautiful frame to the skip?


No need for that I am sure.

Some thoughts;

1) is the stem steel or aluminium?

2) do you really need to move the stem in the short run? (you can usually service the headset and repaint the frame with the stem still in if you need to....) and you will be able to ride the bike

3) To soak over a long period, fit a cork to the bottom the steerer tube and fill the steerer from the top with penetrating fluid of some kind. Diesel is actually pretty good if you are talking weeks or months.

4) corrosion products (aluminium 'fur' or rust from steel) expand greatly vs the native metal. However most of the swelling occurs because of water in the structure of the oxide. Half or more of the volume and weight of the oxide can easily be water. Thus leaving the parts somewhere hot for a length of time will definitely help. If you install a 5-10W light bulb inside the steerer the heat will (over a period of weeks) gently cook the seized parts. Applying oil when the parts are hot will encourage the oil to be sucked into the joint as it cools. Eventually it will come free.

5) don't do anything precipitous unless you have thought it through very carefully. Err in haste, repent at leisure...

cheers
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Valbrona
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Joined: 7 Feb 2011, 4:49pm

Re: Forks stuck fast

Postby Valbrona » 28 Aug 2014, 2:33am

If you do the MickF thing you could cut a hole through the steerer stump and slide through a steel rod for extra leverage, and the forks could go in a bench vice.
I should coco.

Brucey
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Re: Forks stuck fast

Postby Brucey » 28 Aug 2014, 6:51am

unfortunately if you do that the parts will fail at somewhat less than 1/3 the load in torsion vs an intact stem, which is not terribly helpful.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

tim-b
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Joined: 10 Oct 2009, 8:20am

Re: Forks stuck fast

Postby tim-b » 28 Aug 2014, 6:54am

Hi

Engineering query from a non-engineer...could this be machined out?
Chop off flush with the steerer, drill and finally ream to size.

I'm curious because I see many similar threads involving copious quantities of anything from cola to drain cleaner and time, or a big vice and a bigger lever

Regards
tim-b
~~~~¯\(ツ)/¯~~~~

Brucey
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Re: Forks stuck fast

Postby Brucey » 28 Aug 2014, 7:01am

yes you can do that, but doing it in such a way as the steerer is not in any way damaged is quite difficult. A steerer that is weakened and may fail later is no good to anyone; it is a safety critical component.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

tim-b
Posts: 1675
Joined: 10 Oct 2009, 8:20am

Re: Forks stuck fast

Postby tim-b » 28 Aug 2014, 7:19am

Hi

Thanks Brucey
So that (...the steerer is not in any way damaged...) will be why

Regards
tim-b
~~~~¯\(ツ)/¯~~~~

Edwards
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Joined: 16 Mar 2007, 10:09pm
Location: Birmingham

Re: Forks stuck fast

Postby Edwards » 28 Aug 2014, 8:06am

If you are prepared to scrap the whole thing, then thumping the hell out of the stem will only ruin that and the Headset.

Put the stem in a vice so that it can slide. With the frame supported and the upper headset nut against the vice. Take one big heavy hammer (2 to 4 LB) and then assist the stem out by hitting the stem on the forward part (this will not work with a no reach stem).
Keith Edwards
I do not care about spelling and grammar

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Forks stuck fast

Postby Brucey » 28 Aug 2014, 9:09am

a word of warning; if you do that, you definitely can't hit it very hard without causing other damage.

The reason for this is that the core of the threaded part of the steerer is only ~0.6 to 0.8mm wall thickness (depending on how the threads have been cut) and it is very easy to knacker the threads on the steerer or simply cause the steerer itself to start to crumple. Anything more than a brisk tap with a 1/2lb hammer will stuff something up here.

I have successfully removed countless seized stems and modest, (and preferably prolonged) heating is usually the key, for the reasons I have previously described.

A few months ago I saved an SBDU frame and a cinelli stem from further mutilation by using a hot air gun with a special nozzle that blew up the steerer. It took several hours for the heating to be effective, but by careful use of wet rags etc I did not damage the paint on the head tube or even the seal on the lower race of the (C-record) headset. BTW when used on hot parts (100C to 200C), ATF makes an excellent penetrating oil.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~