Hydraulic suspension damper

The invention relates to a hydraulic damper (1), in particular for the suspension system of a motor vehicle comprising a tube (2) filled with working liquid, inside of which a slidable piston assembly (3) is placed. To increase an amount of dissipated energy during extremely fast compression strokes, the damper (1) is provided with an additional compression valve system (17a), preferably in a form of a preassembled add-on device, which is attached to the piston rod (4) in a compression chamber (10) and comprises a hollow main body (18a) surrounding the piston rod (4) and provided with a substantially flat first abutment surface (19) with a radially inner portion and a radially outer portion defining the close position of the system (17a), and at least one channel (20) the inlet of which is located within the area of the first abutment surface (19), a compression spring (24) supported within the hollow main body (18a) underneath the first abutment surface (19), a substantially rigid and relatively thin plate (26a) biased by the spring (24) against a second abutment surface (27) defining the open position of the system (17a), wherein the plate is free to deflect and displace between said open position and said close position, and the outside diameter of said hollow main body (18a) is less than the inner diameter of the tube (2) and the hollow main body (18a) is provided with an annular groove (21) inside of which a cross-cut ring (22) is disposed to form a sliding fit of the hollow main body (18) within the tube (2).