wilmer has developed a slight 'shudder' and grinding groaning noise on the front brake - but only when i'm slowing from about 5mph to a stop. it doesn't occur when i apply the brake at higher speeds, and it seems to go away once she's warmed up a little.

i'll be having a look at the brake pads for wear, etc., but if anybody's had this problem before and could point me in the direction of another possible cause i'd be grateful. brake fluid level? something loose somewhere?