How is the bail system on a CAT 627B supposed to work, and what should I check if it's not functioning?

[Gryks Machines]

I've got a Caterpillar 627B scraper, and the bail has never worked since I got it. I checked the manual, but it's not very clear.

1. Bail doesn't move at all
2. Other hydraulics are working fine
3. No visible leaks or damage

How is the bail system supposed to work on this machine? And what are the first things I should check-hydraulics, linkage, or controls? Any advice is appreciated