brake lever adjuster screw woes -removing knackered hex bolt

To cut a long story short...I'm a walking disaster zone. If it can go wrong it will and after spending hundreds on trying to have a nice bike I've messed up again :facepalm:

The problem in question is with a new (used) pair of hydraulic brakes I bought. They work fine but the lever was loose and way out of adjustment. An easy fix, the travel adjuster bolt just needs fiddling with.... :roll: it's duffed up. Too messed up to fit the right size allen key but not bad enough to fit the next size up. I've tried every trick I know with no luck and I can't use pliers as it's right inside the lever groove meaning even long nose pliers won't fit. I have another bolt to go in from a donor lever but can't get this one out.

Does anyone have any advice? For reference it's the hex screw pointed to in this pic.

Re:

Have you tried a torx bit? Often you can get one of those to grip in a mangled hex head, especially in something that won't have a lot of force holding it in place like an adjuster screw.

Re:

We have all been there. The worst usually is having a unique small part which you are fitting and you say to yourself ‘I must not drop this’ and a split-second later you drop it and it disappears under the workbench.

But....in these circumstances I adopt the following rules:

1 STOP....really Stop....don’t fiddle out of frustration and make it worse
2 assess
3 consult
4 prepare
5 act

Right...this one. Yes I know that bolt. It will have been put in with blue Loctite. My plan would be:

Get something on it to reduce the grab from the Loctite. This is really important. So...GT85, WD40 or PLusGas - give it a good soak and leave it 24 hrs

Yes, a Torx might be a good idea. Check it out for fit. But don’t round it off any more.

A small flathead screwdriver of high quality can also do it. You can exploit the irregularity of the ragged hex hole. Just try a variety of screwdrivers - Stanley, or equivalent - and you can feel if you can work it in and get a good purchase. At a pinch, you can hammer it in gently.

Next time, always soak a bolt like this, and use a very high quality Allen key such as Park or Stanley.

Good luck, as I say...we’ve all been there.

Re:

Cheers guys. To confirm it isnt seized as I have moved it but after a bit of adjustment it rounded off too much. I have managed to dremel a small slot in it for a screwdriver and managed to move it a bit more but my screwdriver was too wide for the channel. Have just got a smaller blade so hoping that does it

Re:

I know exactly what you are on about having dismantled one of those with a broken bar clamp the other day, what a bloody mare.