A pressure wave damper in a hydraulic system for actuating a friction clutch of a motor vehicle, which defines a sinuous path for a fluid of the hydraulic system is provided. The pressure wave damper, along the sinuous path, has a hydraulic pressure chamber elastically expandable by the fluid. The hydraulic pressure chamber is partially delimited by a resilient wall that is presented by a resilient vessel inside the hydraulic pressure chamber. An elastically compressible air chamber is formed inside the resilient vessel. One or more air channels place the air chamber in communication with air vent openings.