There are several generations of "Zone VI" view cameras. The first were re-badged Wista (or perhaps Tachihara) featherweight 4x5 cameras. Then in the late 1980s, Fred Picker had Ron Wisner (who was already making his own cameras) design a more capable camera for Zone VI. These were heavier machines with more extension, movements, and interchangeable bellows. These were made for coupe of years, until Picker and Wisner had a falling-out. So FP had Richard Ritter reverse-engineer the Wisner camera (with a few small improvements ) and offer that one for sale. Which they did for a number of years; my own 4x5 is one of those, from 1992. It was around this time that Z-VI began to advertise an 8x10 field camera, an upscaled version of the Ritter design. These continued in production when FP sold Z-VI to Calumet, around 1995. Calumet redesigned those cameras as the 'lightweight', using aluminum hardware rather than brass, along with a few changes like a satin finish. These were in production until the mid-2000s, when Calumet discontinued most everything with the Zone VI brand.
I've written this long-winded (but mostly accurate) history is because solving your problems depends on which Zone VI camera you have. Can you post a picture of yours, so we can understand this? You mention having used your camera for 40 years... I wasn't aware of them manufacturing 8x10s that far back.
A side note; I've been using a Ritter-designed, Vermont-made 4x5 Z-VI since 1992. I've worked it hard (and made a fair amount of money with it). The complaints you mention make me think we don't have the same generation of camera. I've recently seen an 8x10 Z-VI for sale at a local store, and it is definitely a scaled-up 4x5. Admittedly the folding field design is not the optimum choice for tabletop or macro- although I can and have done so successfully. Most of my work with mine has been landscape and architecture (in the 90s my clients were amused by my wooden camera).
Two more things; If you want your camera repaired send it to Richard Ritter (
www.lg4mat.net), and if you want to shoot tabletop and close-up, get a used Sinar f2.