Never had it with the bike, but me and a buddy were travelling down to London in his car once, at a speed somewhat in excess of the posted limit, when there was a bang followed by a scraping noise, and the car started pulling to the right
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He applied the brakes, the noise and the pulling got worse, but he managed to get the stopped safely.
We got out, went straight to the right front wheel to see what had happened, we were both at this point thinking 'blowout', but the tyroe was still inflated, the wheel however was covered in tiny shiny flakes of aluminium, and was hot to the touch. We jacked the car up, removed the wheel, and discovered that when he'd done a brake pad change the previous week, he'd forgotten to tighten the two bolts securing the caliper to the hub
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The lower bolt was just loose, but the upper bolt had come out, causing the caliper to fall against the wheel rim, causing the scraping noise. Of course applying the brakes had caused the caliper to try nd push away from the disc and dig into the wheel causing it to try and pull the car to the side!
Of course the original bolt was nowhere to be seen, but fortunately we had some tools in the boot, so we started trying various other bolts from the car to see what fitted.
For the record if you are ever in this predicament, Ford (Europe) use the same thread for the caliper retaining bolts as they do for the rear seatbelt mountings
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Obviously ever since then i've been quite anal about checking nuts and bolts after I, or anyone else, has done work on any of my vehicles