
Now, it seems from what you sere saying that the ram itself is OK and it's more likely the leakage return that is leaking.
The return is a rubber spigot moulded into a rubber collar that wraps around the ram. This can break/perish and repairs are possible. It's been described before and a search should bring up the various methods used. I've seen somewhere a new collar being fashioned out of a jubilee clip with a copper spigot soldered to it. Others have done a temporary repair using instant gasket but LHM appears to attack it after a while.
This picture shows the arrangement...

I was nattering to Martin at Pleiades about rams the other day. Sadly they are not really repairable if they leak on the ram itself. It might be worth a natter with him on leaky returns though.
Another thing to check is that the return pipe goes up and ends in a junction with four "arms" on it. It is possible this junction is leaking and LHM is running down the return pipe and making it look as if the ram is leaking. The junction is up near where the large braided pipes terminate.