[Kurt in NJ]

I consider all modern production wheel cylinders suspect, and take apart for inspection of drilled passages, many times the bleeder hole is drilled 1/2 way down causing trapped air, and fluid passages under cup lips
I don't know about macs quality, never bought from them, but every part I was supplied by owners to fix their car didn't work out and was replaced soon after if it worked to begin with, perhaps they have changed after being bought out