I have a flat spring highwall with a SST but it wont set.  Everything works as a normal trigger however.   

Here is the embarrassing thing: a few years ago I wanted to see if a double set trigger assembly would fit.  I tried to swap some parts, saw that it wouldn't work, and then swapped them back.  At least I think I swapped them back correctly.  I can't remember if this problem started at that time or not, all I know is it isn't working now.  Looking at the SST diagram I think I have the right parts installed.   

Any advice is appreciated.

I have removed the trigger assembly from that gun as well as a functioning low wall.  The high wall trigger can now be set, but it doesn't 'click' when set.  It also relies on gravity to lower the knockoff or else nothing will catch.  The low wall trigger makes a nice solid 'click' and can be set in any orientation.

The knockoff moves with the trigger just as in the functioning low wall.

Thanks for helping out.

I've spent countless hours working on Winchester single set triggers and found that each one is unique. The last one I worked on, I made from an original trigger by drilling it out and filing the little notch for the trigger catch. I finally had to take some off the bottom of the hook to make it work. I found that even changing out knockouts will either make the trigger work or not. It's just a matter of a thousandth or two of an inch. I haven't found a good replacement knock-off spring yet that I'm satisfied with. The last good ones I had were made by the now defunct Ballard Rifle Company.  It's really hard to give advice unless you have the trigger and tang in hand

chawk wrote on May 4^th, 2023 at 6:24pm:

Are these all original parts or replacements?

Since these are original parts and we're once working, I don't suggest you remove any metal from anything or try to make adjustments by bending the knock off spring. The 2 most common things you can do is back off the little set screw in the trigger about a quarter of a turn and see if that helps but I suspect you've already done that. The the other thing that you can do is to back off the knock off spring screw about a 1/2 a turn and see if that helps.  Normally that screw should be in all the way but sometimes it helps to back it off.