Bicycle Mechanics - snapped it...grrr

so i just snapped a 1/2 inch bolt trying to use the sheldon brown method for removing a stubborn fixed cup. suggestions?

i liquid wrench'ed it and let it sit for a while. is this an lbs job? can they remove it, given my bad luck?

That would be the safe bet.

Oughta make Sheldon Brown remove it. ;)

so i just snapped a 1/2 inch bolt trying to use the sheldon brown method for removing a stubborn fixed cup. suggestions?

i liquid wrench'ed it and let it sit for a while. is this an lbs job? can they remove it, given my bad luck?That's really stuck!!Wonder if some idiot loctited in in.May have to be cut out.

Seems obvious, but... Get a bigger bolt?

same problem here just the other day :mad: .....I finally gave up and just did the following: removed all the junk I could from the adjustable cup side, then saturated the bearings with wd-40, and then stuck plastic shafted q-tips in and was able to clean the bearings that way. Then I just greased everything up, put it all back together, and so far, everything seems to be ok. It helped that my fingers are long and thin.....made it fairly easy to reach thru the bottom bracket shell and reach the bearings.

Good luck,

mark

Yup, some fixed cups really are "fixed"!

so i just snapped a 1/2 inch bolt trying to use the sheldon brown method for removing a stubborn fixed cup. suggestions?

i liquid wrench'ed it and let it sit for a while. is this an lbs job? can they remove it, given my bad luck?Ya turning it the right way? Not such a dum question, cuz it happens.

Big vise, mounted to a heavy bench, clamp the cup flats in the vice and get a freind to help you turn the frame

...trying to use the sheldon brown method for removing a stubborn fixed cup. ?


Can someone give me a quick summary of the "sheldon brown method"?

Can someone give me a quick summary of the "sheldon brown method"?
Here is a link to the method:

http://sheldonbrown.com/tooltips/bbcups.html

Doc

On my Bulldozer when I can’t get a bolt lose with WD-40 and a cheater pipe. I put the rose bud on the blow torch and heat it up. Works ever time but other things can tend to melt so use caution.

Maybe a stronger bolt? Try getting a grade 8 bolt from an auto parts store. It should handle quite a bit more torque. Or maybe a 5/8" like Sheldon Brown now uses?

However, unless you are replacing the cup, do like forensicchemist and just clean the old one in place and get on with it. At least you know it's not going to loosen up on you down the road!

Here is a link to the method:

http://sheldonbrown.com/tooltips/bbcups.html

Doc

Thanks Doc.

Interesting technique. I trust Sheldon when he says the bearing surfaces won't be damaged, but I cringed when I saw the washers pressed up against the cups in the cut away section, and knowing the amount of force generated through the mechanical advantage of the screw.

Rev Chuck probably has the best solution. You really need to make sure you know what type of threads (right or left-hand) you have.

Big vise, mounted to a heavy bench, clamp the cup flats in the vice and get a freind to help you turn the frame

Damn straight. Nothing is more satisfying than after a couple of skinned knuckles clamping that bad boy in a vice and twisting as hard as you can :)

Maybe a stronger bolt? Try getting a grade 8 bolt from an auto parts store. It should handle quite a bit more torque. Or maybe a 5/8" like Sheldon Brown now uses?



You can get a Grade 8 bolt at just about any hardware store, included the Home Despot. Grade 8 is the strongest commercially available fastener material. Bolt grades are marked by tick-marks on the head. Don't ask me why, but there are two less tick-marks than the grade of the bolt:

Grade 8 = 6 tick marks (material strength = 150,000 lbs per square inch)
Grade 5 = 3 tick marks (material strength = 120,000 lbs per square inch)

The bench vise can work, but ive had too many ugly slips with that one(since the faces are pretty bad by then :rolleyes: . At the car shop(where I do a lot of my bike stuff too) We resort to heat. It doesnt have to be ferocious heat, just enough to expand the shell of the bb, in conjunction with the wrench or vise force.
Another trick they taught me at aircraft mech school is to... tighten first. That's right, turn it tight forcefully, then loosen. It is really an odd concept, but it works usually. That assumes it still can, might be surprised ;)

Yup, heat it up before your next try. If it is Loctite a hair dryer on high will usually do the trick.

well i'm definitely turning it the right way. it's an italian frame and i'm turning the ratchet clockwise (which *should* loosen the fixed cup - as opposed to turning the nut with a wrench.) i've considered the vise option but i don't know what exactly the vise would get a good purchase on; there are three notches and of course the slightly serrated edge of the cup itself, so i'm assuming that's what it would grip. as much as i hate to do it, i'm thinking i'll just take it in. i don't want to damage the shell threading and hopefully the shop will have an easier time getting it out.

peanut butter or mayonaise. or put it in th fridge for a while and then hit it with a big hammer.

Italian frame, but for sure it's italian thread?

well that's the thing, the shell is 70mm (italian size) so i'm assuming it is italian threaded (i know about assuming...) but at this point maybe it's worth trying the other direction. maybe mtbiker's tightening and then loosening trick would work in that sense

what the heck, can't do any harm at this point...

>>Big vise, mounted to a heavy bench, clamp the cup flats in the vice and get a freind to help you turn
>>the frame

>Damn straight. Nothing is more satisfying than after a couple of skinned knuckles clamping that bad
>boy in a vice and twisting as hard as you can

Don't discount the vice method. Way back when I was a bike newbie (30+ years ago), I used that method to disassemble my BB for the first time for new balls and regreasing. Worked just fine, and I didn't have any help. (But, maybe that was just newbie dumb-luck?)

Mike
Juneau Alaska

I don't know why I didn't think of it earlier, but the other way I used to get them off was to weld a big nut on the outside face. from the outside nut, one can get all the force in the world on it.

Update: I took the frame into bikeworks and they had the fixed cup out in 20 minutes, and they corrected my misaligned fork! I guess somethings are worth taking in. Thanks to everyone and their suggestions.