hitachi main boom rams leaking

i have a hitachi ex165 to change main boom ram seals sounds straightforward but lifes never that simple the ram in question has been giving bother this last few months and has already been resealed twice before (by a reputable company) now i am stuck with the job of fixing it . before i go pulling it apart is there any reason this could be happening i looked over the rod still in place and it has no visible markings chips burrs or pitting my only other thought was has the wrong seals been fitted and every time the next man just matches up what comes out



thanks for reading paul