A hydraulic brake system includes a body with cavities, a vacuum brake booster port, a first caliber port and a channel system defined therein. The first switch is positioned adjacent a first side of the locking bar and the first movable plate is positioned to slidably engage a groove on the first side of the locking bar. An electrically insulating etch-stop layer that comprises a second material different from the first material, extends on the first electrically insulating layer and has a second opening therein. and preferably about 475\xb0 to about 550\xb0 C.