Rear brake lockup after hydroboost install

[knomadd]

Hydroboost will not change how your brakes operate. They will lock at the same pressure with either booster. A hydroboost simply reaches that pressure sooner in the pedal travel and can achieve higher pressures than a vacuum booster. If the booster is the only thing that changed and an emergency stop situation is what caused the brakes to lock up, not during normal driving, then everything should be working correctly (assuming everything worked correctly prior to the change to hydroboost). If you're getting brake lock up in normal driving situations then either you're pressing too hard (a hydroboost takes less foot pressure to achieve the same brake pressure as vacuum) or you need to add an adjustable proportioning valve between the master and rear brakes to reduce the amount of pressure delivered to the rear.

With hydroboost in my GTO and my C10, the brake response is much like a new vehicle. It doesn't take a lot of force from my right leg to make either stop. And they both stop sooner than they ever did with a vacuum booster. Both vehicles are disc/drum and I've never locked up either one. But I've never tried or had to make an emergency stop.