RADBMX.CO.UK
Technical & Reference Section => Tech and Restoration => Topic started by: scott30 on April 13, 2009, 11:57 AM
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hi all got a dyno frame i need to strip so i can take it to the chromers to get the chrome taken off as its flaked in places but haveing problems the seat post is stuck in the frame ive managed to get the crank off but the cups dont seem to want to come out and ive also got probs getting the stem out the forks ive taken the stem bolt right out or do i need to put it back in a little so the wedge is still attached to get it out it seems its stuck in the forks any help would be great thanks as havent built any bmxs since the late 80s :daumenhoch: cheers all scott
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get acces to a vice stick the post in it and twist ..soak in wd40 prior to this .. failing that look out for the nearest skip 8)
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Hold seat post in a vice, warm up the seat tube and then use the frame for leverage.
Put the stem bolt back in, make sure you release the wedge by tapping the stem bolt down, sometimes then, the wedge may drop out of the the steerer tube when you unscrew the bolt again. Failing that, its just brute force. Refit the bars or an old seat tube and fit and old wheel to give you more leverage.
Lots of WD40 and soak time usually helps.
The bearing cups will come out, just hit them hard with a drift from the other side.
Good luck fella
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get acces to a vice stick the post in it and twist ..soak in wd40 prior to this .. failing that look out for the nearest skip 8)
thanks for that top pit crew chief..............ffs
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if you can mate leave it soaking in diesel over night or plus gas, wd40 evapourates after a period of time, i had success with plus gas and a hack saw but the seat post wasnt visible above the frame tube,so dont cut anything,mine was a last resort, also a bit of heat as suggested, take your time , keep doing a bit, soaking it and returning when the frustration gets a bit much, it will come out , dont skip it :)
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if you can mate leave it soaking in diesel over night or plus gas, wd40 evapourates after a period of time, i had success with plus gas and a hack saw but the seat post wasnt visible above the frame tube,so dont cut anything,mine was a last resort, also a bit of heat as suggested, take your time , keep doing a bit, soaking it and returning when the frustration gets a bit much, it will come out , dont skip it :)
WHS ^^^^
Also, give the seatpost a good few whacks with a large and heavy club hammer to break the seal between it and the seat tube :daumenhoch:.
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http://www.sheldonbrown.com/stuck-seatposts.html
note - depends on the 2 metals. If you got ali against steel - then something with ammonia will assist - and that oil based will probably not help.
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thanks for the advice guys will try it tomorrow if the weathers good :daumenhoch:
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right guys ive got the stem and forks off now and my dad has got the bb cups and headset cups out to ive bent the seat tube out abit and my dad heated the seat tube up but the post isnt moveing is there anything else i can try :daumenhoch: cheers scott
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don't use the method used by some"rocket" in the states on this s&m dirtbike. ouch. why? is all I can say :'(
(http://www.radbmx.co.uk/archive/albums/l2/philtor210/bike%20stuff/100_1316.jpg)
(http://www.radbmx.co.uk/archive/albums/l2/philtor210/bike%20stuff/100_1320.jpg)
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Heres what u need to do- Drill a hole thru the post a few inches up from the frame and put a nut and bolt thru it.Clamp on some mole grips arond the bolt (this will stop them slipping). Get a blow torch and gently heat the frame to expand it. Tap the top of the seat tube with a hammer to crack the joint. Then try and twist the seat tube until it comes out. It can be a right barsterd but dont expect to save the post. If that fails, shout a load of harsh language and hurl the lot across the garden.I find that works....
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anyone ever thought about smashing it back in?if there aint much of it still visible above the seat post tube meaning you can defo get another one in then what wont come out may as well be driven right in,or is this a dip shit idea????? :D
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Copied this from singlereackworld, which was copies from elsewhere.
Copied from other forum but may be of use to someone in your position.
"Machinist's Workshop magazine actually tested penetrants for break out torque on rusted nuts. Significant results! They are below, as forwarded by an ex-student and professional machinist, Bud Baker.
*Don't forget the April 2007 "Machinist's Workshop" magazine comparison
test.*
**
*They arranged a subjective test of all the popular penetrants with
the control being the torque required to remove the nut from a
"scientifically rusted" environment.*
**
*Penetrating oil ..... Average load*
None ..................... 516 pounds
WD-40 .................. 238 pounds
PB Blaster ............. 214 pounds
Liquid Wrench ..... 127 pounds
Kano Kroil ............ 106 pounds
ATF-Acetone mix....53 pounds
*The ATF-Acetone mix was a "home brew" mix of 50% acetone - 50% automatic transmission fluid.*
*Note the "home brew" was better than any commercial product in this one
particular test. Our local machinist group mixed up a batch and we all now
use it with equally good results. Note also that "Liquid Wrench" is about
as good as "Kroil" for about 20% of the price. * "
So maybe some of that but failing the above get seatpost in a bench vice and use frame as leverage.
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rite guys ive still not got this seat post out :( i drilled a hole through the post and put a screw driver tru but it just ripped the seat post so ive ended up cutting the post off about half inch b4 seat tube and still cant get it to go down into seat tube can anyone help me or anyone up to doing it for me any help would be grate thanks :daumenhoch: cheers scott
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rite guys ive still not got this seat post out :( i drilled a hole through the post and put a screw driver tru but it just ripped the seat post so ive ended up cutting the post off about half inch b4 seat tube and still cant get it to go down into seat tube can anyone help me or anyone up to doing it for me any help would be grate thanks :daumenhoch: cheers scott
that is what you didnt want to happen.... :-\
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this looks like the last resort then mate...
(http://www.radbmx.co.uk/archive/albums/y77/sawzall717/MRD001.jpg) :shocked:
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The thing you have to establish is this;
Are you trying too hard to preserve the frame. ie; the chrome or paint?
Is it going to be a rider or a carpet creeper?
It appears that you are not really trying hard enough, if the answers to the above are; yes, and carpet creeper. Get some proper HEAT on it, hot and fast. The trick is to get the frame hotter than the post, to allow expansion. If its gonna be a show bike, get it cherry red! It will come out, I promise you.
I am afraid to say that cutting the post down, you have only added to your problems. Get something welded back onto it to, to assist.
It looks like a drilling out, as suggested above, is the only answer now if its gonna be a rider, as too much heat serioussly compromises the strength of the frame.
Before you cut it down, you stood a chance, but I doubt that now?
Godd luck, but Sorry. Ad :daumenhoch:
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you need to get that outer tube red hot :knuppel2:i had trouble with my curtis frame i put engine oil down the tube over night then hit with the torch i got it that hot the remaining oil in the tube caught lite like a flamethhrower :2funny:once that went out i used some siltsons on the post as the harder you turn the more they grip got there in the end good luck :)