[oldopelguy]

hoses

Opels are fairly well known for having the front rubber hoses fail in such a way as to act like check valves, letting more fluid in but not letting the fluid from the calipers back to the master cylinder. It is, after all, 30 year old rubber. You may want to replace all three of the lines before you pull the master cylinder out again; they are much easier.

 

[oldopelguy]

only good test I know of

The only good way I've ever found to test the hoses is to disconnect both ends of each hose and throw them away. Install new ones, bleed brakes, and see if the problem is fixed.

Really, this is almost as common/serious/important as replacing the rubber wiring in the headlights. I would place it higher on the importance scale than even the Weber carb or Pertronics ignition.

Who cars how fast the car can accelerate when it is going right into the back of a truck?