[qcj]

Chester, the dump port is where mine was leaking also.  Mine was caused from a bad dump valve where the internal seals were not doing their job. After I rebuilt the valve all was well.  But as Tom said there can be several things that cause this.  It just so happen this was my problem.  Most of the time the valves need rebuilding anyway so this is a good place to start.  The parts to rebuild the valve are inexpensive.