ABS hydroelectric unit defective?

Hello together, have problems with the brakes of my CV BJ. 2002 1.8 VVTi again and again lately. On a workshop visit I was informed that my front right brake cylinder is heavy and it does not return properly. So this was exchanged. A short time later I received a call from the workshop, in which I was informed that the brake can not be ventilated at the front and I still need a new brake hose. As far as OK. When I am there today my friend said that he still has problems with the grinding brakes during the test drive, and he suspects a defect in the ABS hydro-power unit. But before he wants to fix something, I should still drive to Toyota because they might know the problem. Unfortunately, it was not so. The workshop master was perplexed and accused after the information about the suspicions of the friendly, e.g. the ABS hydro-power unit. It is probably a defective coil or something. M cost for aggregate 1850 € + installation. So approx. 2000€ In addition, there might be a set of complete brake discs and blocks at the front and at the back, as the rear left brake caliper is also a bit difficult (same brake circuit). Did any of you have these problems too? Greetings