Assuming they are similar, I've replaced two on my Caroni RFM - RFM was inadvertently used for a metal detector in my in-laws' meadow to find large pieces of a cultipacker.
It was a fairly simple task. Part of the operation was like replacing a belt. Spindle (Caroni calls it a "quill") bolts onto the deck. There is a spanner nut that I was able to cope with using a drift and Channeloks.
EDIT TO ADD - I don't generally care for answers like mine, from people who don't have exactly the equipment being asked about. The post went unanswered long enough I couldn't resist.