Thanks for the advice. I removed the shims and now I'm sure the spring is properly installed.
The shim looks like aluminum. Size 1 5/8" wide x 4 1/8" long. Taper, appx. 1/16" to 3/16". There is a 7/16" slot in the middle for the spring center bolt to slide through, begins at 1 13/16" (from the 1/16" taper end) and continues to the end at 4 1/8".
They are stamped:
BEAR MFG. CO.
POCK ISLAND, ILL
A-2 SELF LOCK
2 ° - 1 3/4"
PAT. JAN. 19:32
<-------- 4 1/8" -------->
______________________
¦ 1/16" taper end
---------- ¦
---------- ¦
______________________¦
¦<--1 13/16 -->¦
