First and foremost, if it is actually a Walker 20 ton you better tear into that old bish and verify internal condition prior to forking over cash for a Seal kit. Secondly, there are 2 variations in regards to the seal material used on main Cylinder, there not interchangeable IRC. It's also a 2 man job to install the ram back into the bore, even a experienced hand can fold seal lip due to the sheer size/weight/awkwardness of the unit design if your not careful.