Had camshaft and 2 rocker arms replaced last year in my '86 300 E and one of the new rocker arms failed/broke along with the camshaft. I took the car to a different technician (B)(very good) and was told the other 10 rocker arms should have been replaced with the camshaft. My car has over 200,000 miles on it. I called the mechanic (A) who replaced the camshaft and rocker arms and he doesn't believe it was anything he had done, in fact he came up with reasons for possible failure. Shouldn't he have seen those things when he was replacing all the parts? I don't want to take me car back to mechanic (A) ever again. Any advice?