I have named my 7x17 Korona "Shakey Jake". Like many aged ULF cameras it suffers from a marked lack of stability at multiple sites. No amount of tightening will keep the front rail even with the base.
Do you have the stabilizers that mount underneath the camera? If you don't, I could post some pictures. They would be simple to make. I think Tsuyoshi Ito ("Shinnya" on APUG) made his. The rails won't stay level without them.