Stiff brake pedal response 9-5 aero

[Poplars]

Have had rear brakes replaced, lines flushed, abs module repaired, and hard vac lines to brake booster replaced.

What are the possibilities? I need to replace my front brakes but I cant see that making the pedal itself feel stiff, thoughts?

[Poplars]

Ive also been replacing all my vac lines but still suspect a vac leak. Replacing coolant bypass valve tomorrow, could it possibly be making a big enough vac leak to cause the brakes to feel stiff?

[Mike Brennan]

If it’s not a hose break it’s likely the booster. Not an easy job