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Removing a seized fixed cup on a BB: your favourite method
Posted: 30 Mar 2022, 8:39pm
by horizon
I'm doing up an old Dawes Die Hard mountain bike and have come across (for the first time!) a cup and cone BB. The non-drive side removed easily (predictably perhaps) but the fixed (drive side) was seized (very predictably AIUI).
There seem to be various ideas on the net for dealing with this but I just wondered if this forum had a go-to favourite method which I would be advised to try first. I've had a go with a 36 mm open headset spanner but I wasn't expecting and didn't get any joy from that - I was more concerned not to wreck the spanner (and/or the flats).
Any thoughts?
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 30 Mar 2022, 9:03pm
by simonineaston
Carefully clamp drive-side cone in bench vice jaws, waft frame with heat gun - or gas torch, even, if refinishing - and turn frame off cone, having first done my best to assertain if cone is English threaded and therefore left-handed.
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 30 Mar 2022, 9:07pm
by slowster
Previous thread -
viewtopic.php?t=146538.
(If you don't have suitable parts to make a tool of the types suggested by Sheldon Brown and R J The Bike Guy, it might be worth asking hoogerbooger if he still has the tool he bought and would be willing to sell/lend it to you.)
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 30 Mar 2022, 9:09pm
by richardfm
Use a nutand bolt through the bottom bracket with some big washers to hold the spanner in place, then whack it with a big hammer, remembering that it is a left hand thread.
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 30 Mar 2022, 9:10pm
by fastpedaller
With axle and bearings removed..... Assuming it's a BSC ie left-hand threaded cup. A 'large as possible' nut and bolt can be clamped together through the hole in the cup, and using a 1/2 inch drive socket and extension, turning clockwise will tighten the grip of the nut/bolt and hopefully unscrew the cup from the frame.
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 30 Mar 2022, 9:27pm
by Des49
On the attached pic for square taper BBs I use the fixed cup spanner at the top together with the metal pipe which has a flattened end to slide over the spanner.
Once the adjustable cup and spindle are out the spanner is held tightly in place by the long bolt with a piece of metal flat bar and wood that are large enough to cover the BB ends fully. These stop the spanner slipping off and the wood protects the frame paint on the opposite side to the fixed cup.
Often I have had to put a foot onto the end of the bar as a lot of force can be required. But with a long lever like this is it all nicely under control.
In my view it is really important to clamp the spanner to the cup like this, the forces can be high and the spanner and cup flats are thin.
May be worth also padding the chainstay just in case something slips or rubs.
Can be used on a frame only or assembled bike. Just remember that for an english threaded BB the fixed cup is left handed.
(Ignore the adj spanner and tool/bolt in the bottom left corner, these are for the more modern BB without a fixed cup).
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 30 Mar 2022, 9:40pm
by peetee
I use a version of the Des49 method. On one particular aluminium MTB frame my trusty 18” metal vacuum cleaner pipe wasn’t up to the job so I used a willing volunteer as an ‘anchor’ and a five foot length of scaffold pole. It did the job but I’m amazed the steel BB cup didn’t take the frame shell threads with it!
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 30 Mar 2022, 11:09pm
by richardfm
Des49 wrote: ↑30 Mar 2022, 9:27pm
On the attached pic for square taper BBs I use the fixed cup spanner at the top together with the metal pipe which has a flattened end to slide over the spanner.
Once the adjustable cup and spindle are out the spanner is held tightly in place by the long bolt with a piece of metal flat bar and wood that are large enough to cover the BB ends fully. These stop the spanner slipping off and the wood protects the frame paint on the opposite side to the fixed cup.
Often I have had to put a foot onto the end of the bar as a lot of force can be required. But with a long lever like this is it all nicely under control.
In my view it is really important to clamp the spanner to the cup like this, the forces can be high and the spanner and cup flats are thin.
May be worth also padding the chainstay just in case something slips or rubs.
Can be used on a frame only or assembled bike. Just remember that for an english threaded BB the fixed cup is left handed.
(Ignore the adj spanner and tool/bolt in the bottom left corner, these are for the more modern BB without a fixed cup).
That's similar to what I was trying to describe, except I used a hammer where you used a lenght of pipe.
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 31 Mar 2022, 10:49am
by horizon
Thank you very much everyone for these great tips. I did have good results using similar methods on a sealed bearing but unfortunately all my carefully preserved sockets etc were of little use on the cup and cone BB.
I'm going to get some bolts and washers together and try either the Des49 method using a dedicated tool or even the "friction" method where tightening the nut increases the purchase on the cup. I particularly like the latter as it leaves (AFAICS) the flats and tool unscathed.
Thanks again and I will of course post any results!
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 31 Mar 2022, 3:32pm
by a.twiddler
A good drenching and soak in something like Plus Gas beforehand wouldn't go amiss. Need good ventilation though. It's gratifyingly smelly.
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 31 Mar 2022, 3:43pm
by simonineaston
All the best with your endevours - we're all rooting for you!
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 31 Mar 2022, 6:49pm
by Carlton green
I liked the concept of clamping the ‘spanner’ down onto the ‘nut’, definitely a technique to remember.
Plus one for using a long piece of pipe to help, it really does make a vast difference.
I have used fastpedlar’s friction method with success, but each problem is different and YMMV.
As a general rule with stuck fashioners I try to work them both ways. It’s a fine balance but if it won’t slacken then I alternate between tightening and slackening - a bit less toque on the tightening, obviously. Sometimes hammer taps on the stuck item helps too, a bit like how an impact driver works.
Good luck.
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 31 Mar 2022, 8:57pm
by wjhall
Here is the bolt & nut clamp method, although applied to the adjustable cup side after the fixed cup side was removed by clamping the flats in a vice and rotating the whole frame. The adjustable side only had pinholes which could not provide the grip.
Soak in easing oil for several days. There are two thick washers inside the BB, which deform as the nuts are clamped up and provide the necessary friction grip. Probably M12 bolt in this case.
Unlike in the photo, put the bike wheels back on the ground before applying any serious torque.
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 31 Mar 2022, 9:09pm
by thirdcrank
I'd recommend caution with Plus Gas: it's a very effective paint stripper.
Re: Removing a seized fixed cup on a BB: your favourite method
Posted: 1 Apr 2022, 6:07pm
by rogerzilla
I've always got them out with a fixed cup spanner and a mallet. The exception was a Raleigh BB with no standard fixed cup flats. I used the bolt method on that one.