Anyone have their brake pedal go rock hard on hot days?

[Loren]

I've had that problem. I generally chalk it up to pad fade. It's not fluid fade. The pedal goes mushy when your fluid boils. What you're describing (and what I sometimes feel) is that you're giving the pedal a good firm push... the pads just aren't biting. Pad fade.

It just happens so rarely for me that I haven't bothered to change out my pads yet!