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Just bought a bike off of ebay, the helpfull seller negated to mention that the top cap bolt had a ball bearing wedged in it as a home made anti theft device. 

Anyone any idea how to remove said ball bearing? Tried a stanley knife around it to flake out the glue, and when that didnt work, a drill. After that i ran out of patience/ideas. I dont care about writing off the stem/topcap, but would prefer to keep the fork intact.

Cheers.

p.s. Happy to post pictures and proof of purchase in case anyone’s suspicious! 

 

 

15 comments

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SpikeBike [132 posts] 1 month ago
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Totally want a picture of the worlds stupidest anti-theft device! 

 

I would say smack it f(carefully) with a hammer? Or heat it up? 

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janusz0 [210 posts] 1 month ago
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I'd destroy the head cap with an angle grinder or maybe a small cold chisel. With luck you will save the stem and only need to replace the cap.
Did the seller only use this "antitheft "device for the stem, or are all the bolts similarly filled, to avoid theft of pedals, handlebars, saddle, etc? Which hole did he fill to stop theft of the whole bicycle? With preventative maintenance of this calibre, I'd be worried about any part that he'd fettled!

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MoutonDeMontagne [116 posts] 1 month ago
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Thankfully I only bought it for the frame, noticed when i was stripping everything off and swore alot. Reckon it was used a commuter, but why do the top cap but none of the other bolts is beyond me, not like its a shiny Chris King or owt! 

I’ll post a picture for your amusement tomorrow SpikeBike! 

Will give the heat option a go first beforw breaking out the hammer and grinder options! 

 

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mc [19 posts] 1 month ago
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I'd probably go for a grinder with a thin disc and just cut vertically through it. Once the ball is out, you might be lucky and get the bolt out with a plain screwdriver.

You don't really want to be grinding aluminium, as it'll clog normal discs, so try and keep contact with any aluminium to a minimum.

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HoarseMann [127 posts] 1 month ago
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Could you unbolt the handlebars from the stem and unscrew the whole stem? If you pull up on the stem whilst unscrewing it there might be enough friction between the bolt and head cap to loosen it.

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srchar [1093 posts] 1 month ago
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Half-inch hole saw through the top cap, using WD40 to keep the cutting face lubed.

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DaSy [865 posts] 1 month ago
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Drill two holes in the top cap and use a pin spanner to undo it, assuming there is enough friction to turn the bolt when turning the cap. If not, stick a bit of superglue around the bolt and try again.

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Tjuice [264 posts] 1 month ago
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I have never tried it, but I thought it was a fairly well known anti-theft tactic.

If the seller did it correctly, he/she would have used super glue, and in which case, you have 2 options:

1) Super glue remover (should break down the glue - quick search on Amazon suggests you can buy it for less than a fiver)

2) Heat (standard super glue is not a great fan of heat).  Do you have one of those cook's blow torches, or perhaps a soldering iron?  Cheaper than super glue remover if you already have the necessary equipment.

If seller used epoxy resin instead of superglue, then you might have more trouble...

The other thing that can cause problems with this is if the ball bearing was too large for the allen key hole and got hammered in...

Good luck!

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Crippledbiker [70 posts] 1 month ago
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It depends on the glue used, and the material of the cap.

I'd suggest putting a couple of drops of acetone on the glue, watching out to avoid drops and runs - if it's superglue (CA), it should more or less kill it.

Epoxies are, uh... Harder. A heatgun might help but likely won't, acetone and isopropyl might work but likely won't.
Taking a dremel to it and cutting a slot into the bearing might work - if nothing else, it might give you the leverage to cause it to pop out!

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EK Spinner [137 posts] 1 month ago
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I am assuming that this is an A head and not a quill stem

Try drilling several holes in the top cap, near the bolt and not so far out that the steerer tube gets damaged, once these holes join together the top cap should break up and the stem can be removed and the forks dropped out of the headset. A pair of vice grips should allow for removal of the offending bolt and all that needs replaced is the top cap and bolt

 

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Drinfinity [115 posts] 1 month ago
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Can you access the other end of the bolt under the star fangled nut? If so, you could maybe use a socket on an extension to run two nuts against each other. Tightening the outer nut should drive the bolt up enough to loosen it from the cap. Then grip the top of the bolt with mole grips to get your nuts off.

problems with this approach-

 

maybe you can’t get in

you might get the two nuts stuck on

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vonhelmet [1350 posts] 1 month ago
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Can you afford to lose any of the steerer? If so - and if the other, better, solutions above fail - you could always saw through the steerer from one side to the other.

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cdean [45 posts] 1 month ago
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If they've used superglue then you should be able to use acetone / nail varnish remover to dissolve the superglue. Try putting some on a cotton bud, or soaking a piece of cotton wool or scrunched up tissue paper and resting it on it – they should keep the acetone in contact with the glue more effectively than just dripping it on. Avoid getting any on the frame as you'll probably damage the paintwork!

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MoutonDeMontagne [116 posts] 4 weeks ago
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Cheers for the responses everyone. Went for the drilling holes in the top cap option, but when drilling between the bolt and topcap, the burr gave enough friction to give the whole thing a twist and get the bolt moving. After that, the drill turning did a great job of undoing the bolt! So stem removed and all sorted.

I will point out that the seller was hugely apologetic - other bolts had been given similar  treatment and he’d removed the bearings, but forgot the topcap. He also offered to cover the cost of getting it sorted by a LBS which restored my faith in ebay/humanity somewhat. Makes a nice change from ‘well you bought it!’ 

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SpikeBike [132 posts] 4 weeks ago
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I still want a picture  1