stuck bolt - rear pannier fixing

[gom]

Both bolts fixing the leg of my rear pannier (and the mudguard stays) simply cannot be shifted. Any ideas?
The bike is a Thorn Audax, 10-15 years old. The bolts may have never been removed since purchase.
I am trying WD40 and penetrating oil (when I can get some). Any suggestions for what to use?
So far I have ruined the Allen Key socket on one nut during first attempt to move it.
Clamping a mole wrench as tight as I can is no good either, it just slips when I turn it.
B****r

 

[ianrauk]

Use the next size up allen key. Knock in with a hammer.
See if that works.

 

[midlife]

Smack in a torx bit, otherwise it's into easy out sort of territory?

 

[Big John]

Depends on how violent you're prepared to go. You could try drilling it out but that would likely remove any thread you had in the hole the bolt fits into. You could then use a tap to re- thread and use a slightly larger bolt or just use a nut & bolt. Another very satisfying way is to use an angle grinder if you have access to one. A great tool for doing some serious damage so go easy with that one. I do like using the angle grinder though 😁

 

[twentysix by twentyfive]

Maybe a bit of hot and cold to try to break the bond between frame and bolt. But careful with the heat

 

[Ian H]

Use a ball-pein hammer or a drift to peen the metal back into the hex recess. Don't overdo it: check at intervals how well the key fits. Just tapping the bolt head might loosen it enough to remove. An impact driver with a hex head might work, though you'd have to support the dropout whilst you hit it (so wheel out).

 

[gom]

Thanks for the suggestions all. No luck yet, but I need to find some more spare time.
I did try hitting it, as it works with the lids of new jam jars, but without supporting the frame. TBD.
I fear I may have to drill it out - or live with the existing rack. I only wanted to change it for a slightly better one that I have spare. 10 min job max I thought!

 

[Cycleops]

Try filing a couple of flats on the bolt and try the mole again or a spanner.

 

[MichaelW2]

How long did you leave wd40 in place.

 

[I like Skol]

With a grinder would be my approach. Remove wheel and rear mech then grind a couple of flats on each side of the hex head. Use a small spanner or molegrips to turn the bolt using the flats.

 

[ebikeerwidnes]

if you don't have a grinder - try cutting a slot using a hacksaw then trying to turn it using a big screwdriver

 

[Ming the Merciless]

Were the bolts put in dry? Usual reason for seizing.

 

[Brooks]

If you can get hold of a Dremel you can carefully cut a slot like others have mentioned. A bit of wd40 and then a screwdriver and that should do the trick!

 

[rogerzilla]

Once the head is off, you can remove whatever it's holding in place and grab the stub with molegrips. Normally it will unscrew easily once the tension is released.

 

[cheys03]

Just thinking what I’d try next…
1. Repair the hex socket as best you can as @Ian H suggests.
2. File two flats in the outside of the head so you can get a spanner on it, something like an 8mm?
3. Wire brush the back of the bolt to remove any surface rust on the thread
4. Apply penetrating oil (PlusGaz) from the back, leave the bike on it’s side overnight so it has a chance of going in to the threads.
5. Heat the bolt a bit using a blow lamp, blowing across the bolt head rather than face on, being careful not to burn the paint or the alloy rack
6. Using the spanner on the head, AND a hex key in the head - try to undo. Have someone hold the bike firmly while you do this. If the spanner slips, use mole grips done up TIGHT, almost impossible to close.

If that didn’t work I’d MIG weld an old spanner to it and undo, the heat alone usually helps but massive lever doesn’t hurt either. Sadly not all garages contain a welder.

I’d not remove the head unless it’s the last option, as it’s something big to grab on to with other tools.

Good luck