Had another go at trueing up the wheels and brake drums. These are better now. Noticed one brake shoe on each wheel started opening long before the other one, found this was because the curve in the metal of the brake shoe was where the cam lobe was trying to open the shoe. Sonnex recomend rounding off the cam lobe's, this is totally wrong, only one lobe should be rounded and the only reason this is required is to let both brake shoes open at the same time.
