I had someone refurbish the hinges on my '50 Chevy COE, using standard Advance Design hinge springs, available from our vendors. There are two per hinge, above and below the hinge strap.
Kent


1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix