How common is is a PS vane pump failure on a 200? I'm at 150K. I have no known alternator issues but I will have the front apart while I replace water pump and alternator. A new PS pump isn't cheap but getting to all of the pulley driven parts on the front is not easy. For right or for wrong, I'm essentially preemptively replacing water pump, alternator, fan pulley, idler, tensioner, etc. Essentially everything that spins with a bearing. I want the next 150K to be like the first 150K, no breakdowns. But I had not thought about the PS pump until I started to remove it to get to the alternator.