[Sagesurfing]

I’ve been dealing with a sloppy break issue for years now. Seems like the breaks lose pressure, particularly after driving high speeds/rpms (freeway driving.)
I find that the peddle starts ok (not the best, but works,) and after driving a bit it just ends up going soft, to the floor. In the past I’ve had to throw the truck in neutral and press the pedal with both feet to get it to slow to a stop.

Just to make it easier, here’s what I’ve tried so far:
- 2018 new break booster
- 2020 (new engine, master cylinder
- 2021 bled the master cylinder again and all the break lines (farthest to closest.)
- 2023:
• replaced front breaks (calipers/pads/rotor)
• replaced rear pads, re-spun the drum
• adjusted the break arm length that goes from the booster to master C
• bled the master and all lines twice more
• seated the breaks (adjusting drums, following seating procedures)
• also ensured the proportioning valve shuttle remained centered during bleeding process and checked to see that it isn’t tripped.

I’ve also checked for vacuum leaks, searched for like leaks etc’…

Again, I drive around town locally and it’s pretty much fine. But as soon as I drive on freeway kinda higher RPM’s, at some point it’ll suddenly lose pressure (pumping does nothing at this point.)
If I stop at that point and just kill the engine for just a couple seconds, the pedal will pressurize again with one pump and I can restart and go again.

Any thoughts?