Snapped allen key head in caliper bolt

[pdig]

Hello and thank you for reading this message.

An allen key head snapped off in the front passenger side caliper lower bolt. Any tips on getting this out? The normal reverse thread bit seems to be the obvious answer. Please see two photos.

Thank you.

[cancunia]

Can you drill a small hole in the centre of the snapped off key, then put a self tapping screw in & pull out with pliers?

[bugsb]

as above
but worth a try its 50/50 bit of super glue on the end of an allen key leave for a while to set unless you have some fast setting spray

[S60D5-185]

Neither of those suggestions will work.

The reason that the head has snapped is that the threads on the far end of that bolt have seized solid in the caliper bracket..

You will need to remove the caliper bracket with the caliper in situ and then drill out the threads of that slider bolt from the back.

[D3GGY]

Originally Posted by S60D5-185

Neither of those suggestions will work.

The reason that the head has snapped is that the threads on the far end of that bolt have seized solid in the caliper bracket..

You will need to remove the caliper bracket with the caliper in situ and then drill out the threads of that slider bolt from the back.

I agree, its a callipers off job and will also result in re-bleeding the brakes as you have to take it out of circuit.

To do your start hole I suggest using a centre drill as they are sturdy and less likely to wander. Readily available from any decent too supplier. Keep opening up until you get to the size recommended for the thread then re-tap the thread before putting in a new pin.

[IainG]

Hi
If it is a good quality Allen key they are designed to snap off cleanly. Sometimes,if you are very lucky you can get them to move and come out with a magnet. If not the idea with the superglue or careful with a bit of quick epoxy.

Iain

[lockstock]

Originally Posted by S60D5-185

Neither of those suggestions will work.

The reason that the head has snapped is that the threads on the far end of that bolt have seized solid in the caliper bracket..

You will need to remove the caliper bracket with the caliper in situ and then drill out the threads of that slider bolt from the back.

Whilst I'm pretty sure you are right, there is one they they could try.

Centre punch the allen key head, drill out, then use a bigger drill as close to size as possible. The use a flat head screw driver on remaining edge of allen head to collapse it in and it should fall out.

Then with a new allen key, or an impact and hex driver try to use the impact to break the allen bolt free. If it doesnt work, nothing lost and it's a caliper off job anyway

[Lou Ferrigno]

It looks to me as if all that has happened is the Allen Key has snapped off in the recess of the sliding pin.
The sliding pin is not damaged so there should be no drilling or tapping necessary to the pin.
All that is necessary is to get the small piece of Allen Key out, so that a new and better quality Allen Key can then be used.
The suggestions of a magnet, epoxy or tiny drill to retrieve the piece all seem good to me and worth a try

[cancunia]

The original question was about getting the snapped allen key out, but agreed that the bigger question is about why it snapped and what to do about it. Personally, I'd try the glue idea, failing that, soak the area with pen oil & try to get the old one out with one of the drilling methods suggested.
The Allen key is likely to be made of tough steel, but with luck it'll be softer in the middle, the centre drill may be a good option if a normal drill won't bite. A centre punch to guide the drill may even do enough to loosen the broken key so that a magnet will work.
Once the the old key comes out, it'll be a case of easing the bolt with a mix of oil & heat, but could well come down to removing the caliper as suggested and drilling the old bolt out.

Good luck with whatever you try.

[Zebster]

It may only be the snapped off end of an Allen key, but it'll almost certainly have twisted itself solidly into the walls of the hex recess before it snapped off. It'll need to be loosened with a centre punch before trying to extract it (which should then be a simple matter, possibly just requiring double-sided tape).