One more idea..This was my problem 2 years ago..
My fronts would lock up and go into a skid. Eventually found out on the 55 there are two adjustments..the usual star wheel adjustment..but also an eccentric where the shoes rest at the top of the backplate. It adjusts the angle that the shoes approach the drum. Somehow I lost my adjustment and the drum would catch the very edge of the shoe and pull the shoe into a "stop" position.
Just a thought..
Keith
