52 Chevy 3600 with a missing safety latch spring. I can only find a little bit of information about this type of latch shown here:

http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm1103.htm

Jim' Old trucks I believe sell the correct spring for this latch which I bought but just can't figure out how to install it. Anyone have the same latch that can share either instructions or some photos?

http://www.oldchevytrucks.com/cart/index.asp?sdes=FPH108