My 9 has 430 hrs on it now and during belly cleaning I found cracks on both steps back side. While standing on the step the crack is forced to close it dosen't figure. I think that a batch of badly welded steps were made. I have been looking at a lot f RV's with that same step 6's 7's and 9's all have the same step with the same problem, better check them folks, I think they can be stop drilled if you catch them when it first starts.