Brakes on 88 Prelude Si 4WS

[etaub1]

Greetings all...

wondering if you guys could help. i'm not handy with cars.

on 4 occasions in two years (including yesterday) my brakes "malfunctioned". hard to explain, except that they seem to lose their "sponginess", pedal seems not to go down to the floor. breaking ability diminishes but still works.

the problem always occurs when it's real hot outside and usually after i've driven a while in stop and go traffic. yesterday it wasn't stop and go but i had driven on the highway for an hour and it was real hot.

any idea what this problem might be? is it an expensive fix? thanks!