96s10 brake booster vacuum leak

Brake pedal whistles and is hard to push. Only happens intermittedly. Mechanic wants to put new brake booster on. This would be 3rd brake booster in 9mos. It’s gotta be something else. What does the vacuum hose connect to from the check valve; where on the intake manifold? If no PVC valve…then what else? Truck runs fine…no fast idle or rough idle and no hesitation.

You can run your finger along the vacuum hose, it goes somewhere on the intake manifold. Is you mechanic adjusting the push rod on the new booster to match it to the master cylinder? Does teh pedal travel seem about right?

No real travel in the pedal…just sinks half way and then gets really hard when vacuum fails. Is it the egr valve or a fuel pressure regulator…hose looks fine. How can you tell? What would make a new brake booster fail so quickly? Push rod seems adjusted okay…this guy also put on a new master cylinder and abs pump. I’m outta money with this truck!

Does your windshield leak? Does your carpet get wet often? Is the foam filter in place and is it still in one piece?

From your description, the push rod is not adjusted correctly.