How do I tighten my front brake?

[Bruce]

Nope, there's just a little circular box-type thing into which I presume the allen bolt behind the front calliper is bolted. The box has a back to it and so I believe it must contain a built-in nut.

Sorry, I should have made all that clear at the start to discourage Mr Aggressive Bruce from biting my head off! I can almost see the mouth-foam ...

That goes to prove my point, you sir are an IDIOT, leave the damn thing alone before you hurt yourself and let either a LBS do it for you, or find a small child in the neighbourhood to fix it for you. And just like last time no foam at the mouth, just pointing out the obvious that perhaps persons, with your clearly challenged mechanical acumen SHOULD NOT be playing around with something as safety critical as the brakes!

 

[XmisterIS]

Any help here?-

http://sheldonbrown.com/gloss_ra-e.html#recessed

Many thanks!

 

[Radius]

So what was the problem? If it was a recessed bolt, then everything everyone has said was correct...
Also, what bike is it?