After six years mine started leaking. I do not know whether it had been a replacement or not. The purchased Ford seal was nowhere close. I searched for 2 weeks to find a seal that would fit at many hydraulic suppliers and found nothing usable. I had heard the replacement from China did not have replaceable seal or at least not the Ford seal. I purchased one anyway from Concours in Carson City Nv. and has been fine for four years.
I replaced many of the cylinder seals years ago an they were simple it do.