PIK-20 Trailer

My PIK-20 factory trailer has a surge brake mechanism with a horizontally mounted gas? shock absorber. The shock absorber has become largely ineffective. When starting out from a stop, the tow hitch will extend rapidly and hit its stop with a jolt. I need to replace the absorber but can find no identifying labeling on it. It is likely original and from Europe somewhere but I cannot find a match. Does anyone know of a replacement possibility without totally removing and replacing the entire undercarriage?