What is a "BPMV unit". Is that their name for the hydraulic controller for the anti-lock brakes? The person who told you everything with rubber parts must be replaced is exactly correct. I'm not sure I would believe the person who said he has done many of these. In my 29 years as a mechanic I've been involved directly with three cases of contaminated fluid and have discussed fewer than a half dozen with others. All of those involved do-it-yourselfers. Experienced mechanics know how easily the fluid can be contaminated accidentally, and they will typically wash their hands before handling any brake parts. To have worked on "many" of these problems, I have to wonder where they're all coming from.

If the unit in question is the hydraulic controller for the anti-lock brakes, I always list that as a part that needs to be replaced. Internal parts are generally not available, partly for liability reasons, but there are valves in it that need to seat perfectly and rubber seats and seals do that better than steel. For a definitive answer I would contact a GM trainer. They know more than what's on their training videos the mechanics watch every month or they would be able to find out for you. If they say it does not need to be replaced, it will have to flushed thoroughly and that's going to be hard to do.

Answered by caradiodoc (expert)
17,303 answers provided