The ram seals supplied by our shop have been manufactured by copying an original seal. They are the exact dimensions of the original but the rubber will feel a little harder than the older seal you are replacing. To fit the seal it will need to be heated up with a hot air gun to make it more pliable. A very blunt screw driver or similar will need to be used with plenty of hydraulic jack fluid, lubrication.
When the seal has heated right through until pliable it should first be squeezed into the housing with the top lip forced into the housing recess. As above.
The seal now needs to be forced in on its self and pushed into the housing. It can then be opened up so that it fits into the housing recess.