I have a 1995 Evinrude 175 outboard, with hydraulic steering. The two hydraulic ram seals (located on either end of the housing which connects to the engine) are leaking like crazy. The seals appear to be metal with a rubber o-ring that surrounds the ram. The metal portion has 4 small holes which look like they would accept a spanner wrench. Are these seals easy to replace? Can you replace these seals, or do you have to replace the whole steeing assembly? Thanks in advance for any advice.