450 SLC - Strange steering problem (On my 1980 US spec car w/ appx. 250,000 miles)

The steering has started to lose it’s self centering action, and the wheel will not come all the way back to center when it is turned to either side. It seems to be binding, but it DOES self center when the wheel is turned less than about 2 inches off center. Any further, and it starts to get sticky. I rebuilt the entire front end this past summer, (A-arm bushings, tie rod ends, idler arm, lower ball joints, steering damper, & sub frame bushings). Everything has been fine until now, and it appears that nothing is wrong when inspected. I have not hit anything with the wheels, so the alignment is O.K., although it almost feels like there is not enough steering castor – that’s the best way to describe it.

I did re-seal the steering gearbox about 5 years ago, and the free play was adjusted properly at that time. It has developed a small amount more free play than when originally redone (I changed the steering shaft coupler recently as well). I don’t know what’s going on.

Do these steering boxes exhibit these symptoms when they wear out? Any other ideas?

THANKS FOR YOUR HELP, EVERYONE!

Just in case anyone wants to know
 

I figured out what was wrong. The relatively new steering damper was at fault. I took it off, and it felt as though it was filled with cement instead of hydraulic oil. Just one for the archives I guess… THANKS