[rjttam]

Thanks Wannabe, it sounds like the same or very similar problem. However, speed or bumps don't create my violent bucking, it's only when I apply moderate braking pressure. I have had input from other forums that give me a strong indication that my brake control has probably developed a problem and needs replacing. I will start with that change first, since the one I have now is 4 years old and probably needs to be replaced with a more up-to-date unit. Thanks again for you interest and information. RJM