172 driver
Sorry ,rechecked the 757 AMM ,both the direct reading gauge AND the flight deck indicator pressures are sensed at the nitrogen end of the brake accumulator.The previous theory still holds good about the cold soak and slightly low precharge pressure .The separator piston in the accumlator has bottomed out towards the nitrogen end of the accumulator with the nitrogen pressure maxed out at 2500psi. There will still be hyd system pressure on the other end of the accumulator (3000 psi).