(technical difficulty ranking* 4/10.....*on the PeterT scale)

Doing some renovation on my steel bike and have two stuck M5 bolts and might need some heavy engineering assistance.

 #1 is in the steel fork, mid fork rack mount eyelet, steel M5 bolt that has been there since new (about 2 years) , had about a 3mm hex socket which is now completely rounded by my attempts to get the bolt undone. Have applied WD40 liberally a number of times, filed some flats on either side to grip with multigrips but refuses to move, I am afraid that if I use more force the head will snap off. The same bolt on the other fork came out without any drama.

 #2 Rear seat stay rack mount, I have had the racks off for 12 months and had put in some pretty anodised  aluminium bolts (with grease) to keep water out but when I tried to remove this one it was not as easy coming out as the similar on on other side , applied a little more force (not much really)  and the head and a few mm of bolt snapped off leaving about 10mm in the eyelet, nicely recessed so I can't get at it.

 The local LBS is not keen to touch them, any suggestions where I might get some heavy assistance at removing / drilling them out or other magic tricks.


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I've had good success with thermal cycling, whacking with a hammer, and WD40. Though Sam's brew sounds interesting.

Basically, the thermal cycling and hammering provide a bit of shock to the joint, causing them the move apart and let the oil in. It can take a few days, but using that technique I've gone from a bolt so seized I can't move it, to one that came out with barely any effort at all.

I want this to be a TV mini series. BOLT season one ...

Here you go:

That's very good

hah that's awesome

Episode #24

A couple of sessions this morning, bashing, WD40 squirting etc did not seem to lead to a solution. This afternoon, on the way to the shop, I stopped off at the garage for another go. I had filed the flats on the bolt head a bit bigger as the shifting spanner kept slipping, the gap between the flats was now pretty close to 5mm so I used a fixed 5mm spanner, damn! felt like it slipped again, but what's this, the flats had been horizontal and now vertical, how could this be, could it be that the "slipping" was actually turning, with hand trembling I fitted the spanner to the flats again and turned, turned and turned and the bolt was out, success !

Thanks for the suggestions, not sure which worked but now ready to fit front and back racks with extremely well greased good steel bolts.

Bolts do occasionally do that - ie having another go another day will sometimes do it.

Also center drive spanners will often move a stuck bolt that is rounded off from a loose shifter.


In passing you may like to read a classic story about a stuck seatpost in the frame of a friend of mine...


and this bloke who is a major bike nerd PLUS a bike mechanic during the day is offering a prize to help de-stuck his bottom bracket...

(comments/ suggestions also feature cola!!)


bees wax is said to be good for making sure bolts don't seize

Any chance of a picture of the modified offending bolt head ? 

And subject the kiddies to Fe2+ porn?


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