A fluid damper assembly for use in a vehicle includes a piston subassembly which includes a plurality of inflow passages and at least one rebound disk for restricting flow of hydraulic fluid through the inflow passages. A rod extends through the piston subassembly to actuate the piston subassembly between a rebound stroke and a compression stroke. An actuator supported by and within the rod includes a piezoelectric device and an amplifier for adjusting the damping force during the rebound stroke, thereby adjusting the suspension of the vehicle. A shaft within the rod is connected to a retainer to transmit motion from the amplifier to compress a spring and disengage the retainer from the rebound disk to allow the rebound disk to flex solely in response to hydraulic fluid pressure from the rebound stroke to open the inflow passages and reduce the damping force during the rebound stroke.