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12 posts • Page 1 of 1
During some routine maintenance I noticed that my rear derailleur hanger was loose.
Both the bolts have hex heads but one was damaged and I couldn't get a hex key into
Any tips for repairing a hex head? The damage appears to mainly be around the top
where it looks like chain has rubbed against it.
I'd like to get new bolts but a mate of mine tried that recently and could't get any
from his LBS.
Dont know how this will work in that area but you could try either of the following
1. Some how tap a flat blade screw driver into where the hex head goes and undo carefully.Note you`ll need a slightly larger driver and you`ll be using the outer edges to get a grip to undo
2. Is it possiable to get a hack saw in and place a small cut/groove into the head and undo using a flat blade driver.
If you go to your local nut and bolt place they will be able to match the threads to replace you bolts etc
I had the same issue last week with two torx bolts on my disc rotors.
I ended up using a chefs blow torch to heat the bolts, then some vise grips to get it moving. The thread lock didn't help, but once I broke the inital bond the bolts unscrewed with my fingers.
'11 Lynskey Cooper CX, '00 Hillbrick Steel Racing (Total Rebuild '10), '09 Electra Townie Original 21D
Some good suggestions there - especially the screwdriver one from revinR1.
Some of the others won't work as the top of the bolt is flush - no protrusion to grip or saw a groove into.
It's also a carbon frame so I'm reluctant to go with a flame thrower!
I think I'll try hard to get new bolts.
Get a small nail punch and a rubber mallet and give the ends of the bolt ( In the frame) a little tap might move them enough to get a screw driver in the head and to give the thread some bite.
2009 Cannondale CAAD9-5,
Single speed GT Avalanche 2.0
Use a torx head socket which is a bit big to fit into the allen head, "press it in" with a hammer. Works well for taking out damaged allen bolts, don't know if I would do it for reinstalling them though as it will make it hard to get out next time. Use a thread lock liquid too.
If all that fails, drill the head out (carefully). You can usually unscrew what is left with your fingers or pliers once the replaceable hanger is out of the way.
So we get the leaders we deserve and we elect, we get the companies and the products that we ask for, right? And we have to ask for different things. – Paul Gilding
but really, that's rubbish. We get none of it because the choices are illusory.
I have run into this problem with a seat post that requires high torque to keep the seat in place. The female hex part of the bolt had rounded out. Bought an "Easy Out" from Bunnings; drilled a hole into the bolt in the middle of the head and the applied the Easy Out. Bolt came out easily.
To avoid a repetition, I bought a stack of stainless steel bolts from a bolt supply shop in Virginia. Cost me about $10-15 for about 30 bolts of various sizes. (were about $2 each from a bike shop) The bolt shops seem to be Aus wide - (I googled them). The SS bolts seem to be much more resilient to burring than titanium or mlld steel bolts.
I would usually grind a cheap Allen Key to fit the bolt, tap it in with a hammer and away you go.
If the head is completely shot, however, an 'Industrial Supplies' mob will be able to sell you a left-handed drill bit that will unscrew the bolt as it bites into the head. Might cost $12, but it could save you a world of pain.
There's also professional bolt removal and thread repair services available, if all else fails.
12 posts • Page 1 of 1
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