Nh 474 conditioner roll

New member here, I bought a 474 haybine last fall and while adjusting things for this springs haying (wishful thinking apparently) I noticed the roll pressure adjustment doesn't appear to be working properly.

When you loosen the roll pressure the crank the threaded rod it's on extends up and when you try to tighten them the crank goes down until it bottoms out . When you look underneath there's still threads

showing. Just wondering if perhaps the pivots are rusted solid or something.

I have the shop manual if I need to remove the assembly.

Thanks in advance.

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Nh 474 conditioner roll