Stainless steel bushings prevent corrosion and wear of the anchor pin hole in the spider. Check the brake spider for worn anchor pin holes, cracks and alignment. With single anchor pin spiders, you should check for anchor pin wear and looseness. If anchor pin looseness is found in the single pin design, a new spider assembly will have to be installed. With double pin design components, you probably only will need to replace the anchor pins and bushings.
Bent spiders can cause tapered lining wear or cause brake shoes to extend past edge of drum.
With everything the same, such as chamber size, brake length, brake lining etc., the shortest push rod stroke will do more braking until it matches the next shortest, etc. This results in faster wear of the brake lining and higher temperatures on the wheel end with the shorter stroke.