a brake problem

[catoichi]

i've looked this problem up and couldn't find any questions for it so here it goes..
I've just bought the car a few months ago so i'm not up on the history of it and am finding and fixing things as money permits. But my brakes are irritating sometimes ( not all the time ) when i'm stopped my brake pedal will give me feedback, it'll sort of " ping " back at me. best description i can give. the first snow of the year the other day , just enough on the ground to make it a bit slick i had to slam the brakes down to stop because it was giving me very hard feedback.
I know enough to know this is the abs system but beyond that i'm clueless. any help??
thanks guys

[nando]

it sounds like normal ABS operation to me.

[azraphale]

I had the same problem on my car, which I think was because the pistons were too extended as all the pads were pretty far gone. New pads all the way around and the problem disappeared entirely.