cant get the air out of the brakes?

It sounds like air is stuck in the ABS system. Here is a video and guide below to help you bleed the brake system correctly.

https://youtu.be/w7gUsj2us0U

and

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

and

https://youtu.be/WDxvEQrMkBg

Please run down these guides and report back.

I'm trusting that they've eliminated the master cylinder as the problem. This thing is more insidious than that. The issue seems to be with the left front...keep getting air in the line. On advice of "expert" caliper piston ? has been changed twice with no resolution. Now we're ready to move on to the hydraulic (ABS) control unit. Used one is $75 and then some substantial labor to get at it and replace. Fearful that this too will not be the answer. Lookinf for any advice I might get. Thanks

Something not adding up here
You don’t have the correct story and or they telling you things not correct
Air does not get into the system on one side do to a defective ABS unit
if have leak , you will be adding fluid
If caliper not releasing check and suspect the hose

Hose will cause premature failure and is not as common and not as easy to diagnose. If piston hard to push back loosen that line at abs. If still tough loosen bleeder on caliper. If easy then suspect internal line failure. Not all failures are visible. Also check for inlet in caliper plugged with rust (rare).

Great addition to this thread! Please feel free to help out whenever you are on the site :)

Cheers, Ken