Parked truck the other day. ambient temp approx 115, coolant temp on gauge approx 225. returned to find extreme brake fade, pedal almost to floor on initial application. I have flushed brake fluid even though truck is only 1 yr old with 3000 miles. Installed castrol lma dot3-4, no help. Incident has occurred several times under similar conditions and is repeatable. My conclusion is that even though coolant temps are not "over the limit" excessive, it is obvious that underhood temps are borderline and that addressing that issue will probably be beneficial all around.