Pictures help. What's the problem with the existing pedestal? If it is a corroded base, there are workarounds.
Most of our boats rigged originally with Yacht Specialties/Merriman steering units still function pretty well. Parts however have to be second hand, as Ys/Merriman is long out of business. Edson parts are usually not compatible.
Changing the whole system to Edson will be expensive. There may be repair options.
Photo guide to step-by-step disassembly of pedestal steering: http://www.ericsonyachts.org/infoexchange/showthread.php?14133-Yacht-Specialties-Pedestal-Disassembly-with-Photos This took longer than expected, often felt like the...
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Here is a photo guide to such pedestals, with links to Edson.
(Yacht Specialties/Merriman binnacle steering manual: https://ericsonyachts.org/ie/resources/merriman-binnacle-catalog.187/ ) ( Edson pedestals: https://backwinded.wordpress.com/2015/12/07/replacing-the-diesel-engines-throttle-shift-and-stop-cables/ also Edson 335 pedestal with Yanmar 3YM30...
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