I had the same problem on a Roadmaster I purchased as a project/moneypit. After resealing the valve to gear, discovered the input housing had a paper gasket that leaked. There isn't supposed to be a paper gasket. I pulled the gear and disassembled it only to discover there was an o-ring on the housing(old and flattened) and the "adapter" that is just inside the main housing had no seal at all! Currently trying to match up some seals from a local hydraulic shop.
Wigman