(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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Have you tried tightening the bolt a little first? That is often enough to start loosening it. I know it sounds a bit counter productive but it works more often than not.

Secondly, have you tried heat? I bit of a blast with a blow torch can work wonders.

Thirdly, ditch the WD40. Make up a batch of home made penetrating fluid with a 50/50 mix of acetone and automatic transmission fluid and use it instead of WD40. (Don't use this immediately prior to applying heat!!)

As for getting the broken bold out, you may have some luck with a bolt extraction tool (like this one: http://www.supercheapauto.com.au/online-store/products/Best-Buy-Scr...). They can be a bit fiddly though.

Alternatively, if there is enough material around the bolt, drill it out and re-thread something slightly larger.

(Please note, I've only used the above on techniques on cars / car parts)

I'm a big fan of the screw/bolt extractor.

what we should have is a ranking system of the technical effort on the title as well.

[Level 1 being changing an inner tube]

this ranks about 4/10? which is 3 levels too hard for me.

I'll add this helpful tip : Steel is overrated.

"Steel is overrated"

mind your words there

Steel is overrated.


Repeat after me, PeterT:

"Steel is real. So is titanium."

Used the right steel for the bolts in the first place, or a bit of grease?

Use a hacksaw to convert the hex head into a standard flat head screw. I find I can get more leverage with a big fat flathead.

Good suggestion - this has worked for me also.

I've used a dremel instead of a hacksaw, but the same idea - you simply make a massive slot across the head and then use the biggest flat screwdriver in your arsenal.

Before you get cranky and go the heavy duty stuff ...

Fork, give it a good dose of boiling water from a full jug and then give it another go with the vice grips. Could get it a tap or two with a cold chisel and hammer just after the boiling water to see if it breaks the grip.
Could try the same with the rack mount but is it on the seat stay or in the seat stay?

like this

Partial success, drilled holes of increasing size through the rear alloy bolt without damaging the thread too much, cleaned the remaining bits of bolt and can screw in ( and out) a steel M5.

The front one remains stubbornly stuck despite the hacksawed slot, will give it more loving attention later.

The take away is ...it is possible because it is an alloy screw and it is a steel frame. But maybe you are going to avoid alloy screws now.

correction, an alloy bolt in an alloy frame. Alloy of steel yes, but still an alloy. Aluminium based alloys are a bad idea on either side of the thread, and never EVER use the same grade of any alloy for both the bolt and hole.


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