[Rick Parker]

Regardless of brand, some of them fail at the area where the knurled axle is secured into the rocker body. The surfaces within in the axle bore pounds out where the knurlings secure the axle. Then the axle "Walks" out of the body. These pictures of one side being cracked might reflect mis-aligned rockers, which strike the valve stem at a slight angle causing loading on one side of the rocker body. Just a thought. Look at stainless rockers.