chudies

hi all

i am a new rider and thought i would share my first near miss
not a major one but enough to scare the bezimbers out of me!
basically, at 40 mph behind a white van man who broke quite hard (in hindsight i was probably too close behind!)
i hit the brakes, and the whole bike went wobbley to say the least
thought i was at the rodeo!
thouught i was heading straight into back of him!
however, managed to steady the monster and calm myself down!
learned - stay further behind, use more front brake
ok, probably a small near miss compared to you experienced riders!

anyways, i am after some ADVICE now please
basically, since my ordeal, the rear brake has felt weaker
and i now hear grinding (metal on metal?) when i use the rear brake
the bike hasnt done 4000 miles yet, and thought the rear brake would last longer
do you all think i need rear pads replaced already??
or, as i was told by the local shop, there is some "grit" that needs to be worn out? thing is that it was worn out after 100 miles!

any advice gratefully received!
cheers