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What the f*ck is this allen bolt size

2296 Views 23 Replies 5 Participants Last post by  KeepTheFeather
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So I want to remove my exhaust to clean the rear caliper and I guess it came with an allen bolt? (bottom one on the pic) Every video I see of someone removing a cbr 250r exhaust shows it with an hex bolt and yet for SOME REASON mine came with this abomination. Soo... Is this normal? And if so does anyone know the size of it so I can buy an adaptor. Thanks lol
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And also yes Im aware the rear brake liquid is low lol
Yeah maybe I will hold off on it then. So I need to remove the back wheel to remove the caliper from the rotor? I did remove the front one and cleaned it and replaced the pads and that was quite easy but I definitely dont want to remove the back wheel thats a bit beyond me.
And yeah I ended up measuring and you were right it was a 6mm! I have no idea why anyone would remove the hex and put this crappy bolt that was also very over tightened I suspect lol
Oh also I shouldve added that im working with the non ABS version
Sorry for responding so many times. So what I wanted to do was pretty much this
So I just wanted to remove the caliper from the rotor so I could access the insides better and be able to clean inside with brake cleaner and put copper paste on the pistons without a problem. So what I did for the front but in this video it just seems I need to remover the exhaust to do it. Do you think I should be doing these things? The only thing that worries me is not having a torque wrench but I memorized how much I needed to turn the caliper screws to snug them back to how they were.
Thanks Tamir!
And btw the chain alignement is still a work under progress lol
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Yeah thats what I ended up doing. Removed the 12mm back bolt and just slid the caliper up instead. Much simpler.

However brace for the sad, dreadfull, depressive and dark end to this.
I cleaner everything, the pistons the calipers, all the pins and right spots lubricated with silicone grease. Put the new pads in, even did a brake fluid bleed that went great.


As I was tightening the 12mm screw, I assume I over tightened it because CRACK. The screw broke. A clean break right at the entrance of the bottom hole. Meaning that now I have the broken tip of the screw screwed in the hole with no way to remove it and to top it off a loose caliper.
Saying I was pissed would be an understatement.
The only solution I see is getting a tow to a nearby garage and hoping they can remove the tip, oh and buying a new screw from Honda, fun!

Im pissed and screwed by a screw.
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Yeah i've cooled off now lol. Thanks! 🙏🙏
I might buy a screw extraction kit. Problem is its sideways, so im worried tapping hard on it might damage something.
Ill probably end up going to the professional to get it out lol
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Yep for sure. Im hoping after I buy all the tools DIYing becomes a money save in the long run 😂
So I couldnt really take a pic of the broke screw today, I will definitely try to tomorow! Here is a pic of where the bolt snapped.
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As for the fix. I dont feel very confident drilling it especially when I cant take the wheels off. Hammer extraction could work but that would take removing the exhaust. Which would take quite a few tools. Allthough I have a long T wrench the muffler ring bolt at the bottom has been fastened up so that I cant get a socket perpendicular to it. So it would take a wrench. My 1/2 wrench is too big for the space. The small normal spanners dont have enough leverage. I think I will rely on the mechanic ofr this issue, because I am not sure what tools are needed. Wouldve been so much easier if garages assembled parts properly :/
Man, sorry to hear about that bolt. That's a surgery you don't want to make a mistake with. Good luck, drill straight, and use plenty of penetrating oil (wd-40 or other).
Thanks man. I ended up removing it by drilling a small hole, then taping a triangular file into the hole and using an adjustable wrench to unscrew it. Was a majer headache and in definitely never making this mistake again!
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I was scanning through posts and found this one. I just want to say OP was a genius by drilling the small hole and taping a cheap file on it. I would never thought that one and you can bet I will remember that trick forever.

Awesome job!
Hahah thank you!
I was very surprised nobody was suggesting this method on videos and forums because its just so simple and works so well.
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