I have been having an ongoing problem with the rear brakes on my 1990 Formula WS6. The drums warp in a very short period of time. I have replaced the drums (iron) three times since I bought the car about 6 years ago. I have had each set 'turned & cut' several times over the years. The problem is that it only takes a couple of weeks after each replacement or cutting for the brakes to develop a 'pulse'. I have replaced every part in the entire rear braking assembly at one time or another trying to find the problem. I have not been successful. I cannot afford converting the drums over to discs. I do not have a problem with the brakes working properly. But, the pulsation when I step on the brakes is an extreme annoyance. Has anyone else had this problem? Does anyone know how to remedy it? Thank you for any help!