Sounds like the problem I had with my 88 accord. Soft brakes when
everything got hot. It got so bad for me that I had to change the
master cylinder, and both wheel cylinders along with flush and bleeding
of the brake system.

But even with all that It didn't help things much. To me all honda's
feel this way. I now have an 2005 odyssey and the first thing I
noticed upon driving it was the soft brakes. Nothing like the old
accord but soft. I drove a number of Nissan's and every one of those
cars had brakes that would bring the car to a halt at the lightest
touch of the pedal.