A hydraulic damper (10) for damping vibrations in the fluid flow path between a hydraulic pressure source and an associated hydraulic consumer comprises a cylinder (11) having a bore (19). A piston (12) is sidably received in the bore and has a sealing means (30) in contact with the bore to define on one side of the sealing means a first chamber (13) for connection with the hydraulic pressure source and on the other side of the sealing means a second chamber (14) for connection with the associated hydraulic consumer. The cylinder has a sealing zone (20) which in a first operative state of the damper is contacted by the sealing means. The piston (12) is capable in response to an increase in hydraulic pressure in the first chamber (13) of moving in the bore to reduce the volume of the second chamber (14) such that eventually the sealing means (30) moves out of the sealing zone to open fluid flow means (22) through which hydraulic fluid can flow from the first chamber to the second chamber. The piston is also being capable in response to an increase in hydraulic pressure in the second chamber (14) of moving in the bore to reduce the volume of the first chamber (13) such that eventually the sealing means moves out of the sealing zone to open fluid flow means (21) through which hydraulic fluid can flow from the second chamber to the first chamber.