A half ounce is real lot. Every year I did a demonstration for my students where I dropped two rubber wheel cylinder lip seals into two beakers with an inch of fresh brake fluid. I added one drop of engine oil or power steering fluid to one of them, then set them on a shelf for one week. At the end of that week, the contaminated seal grew about 20 percent and was soft and mushy. After washing it thoroughly and drying it, the seal shrank back almost to normal size within a few days, but it never regained it normal hardness. It always felt gooey and sticky.
Flushing the brake fluid is usually not enough. The seals all the way back to the rear wheels become contaminated, so to say the power steering fluid floats on top is not the entire story. Once new fluid is introduced, the contamination leaches out of the rubber seals and recontaminates the new fluid. I hope you have good luck with the flush, but the only way I would approach this on my customer's car would be to remove everything with rubber parts, flush the steel lines, then install all new parts that have rubber parts inside them. If they refused to do that, I would gladly recommend some other shops. If they get by that way, more power to them, but if they continue to have problems, it won't be my name that gets mentioned.
Tuesday, February 13th, 2018 AT 7:15 PM