I made a useable spreader from two pieces of 3/4" square bar stock 1' long , a 1" long 3/8" bolt/nut/2washers and a C-clamp. Place the bar stock side by side with bolt/nut/washers about 2" from one end, with the washers outside the bar stock. Tighten the nut finger tight. This holds the bar stock parallel. Put the short end between the ends of the A-arm. Put the C-clamp across the long ends in such a manner as it will pull them together. Measure the distance between the A-arm ends. Tighten the C-clamp, the bolt will act as a fulcrum and the short ends will open and spred the A-arm the specified distance. Install the cross-pin caps and release the C-clamp.