What are the signs of a dieing brake booster?

[quattro90S6]

They work, but the pedal must travel about 3 inches until something happens. Im doing all four corners pads, rotors, and braided lines this weekend and hopefully after it will be gone, but still what could be the symptoms? ALso the brakes do not grip as well as they do on our other 90. Me: 1995 90 quattro with 150K orbitals and can't remember what pads. Other: 1993 90 quattro with 144k stock

[ryoung]

The most common symptom would be that extra pedal effort is needed to stop because you've lost vacuum (and vacuum assist) in the booster for some reason.

With the car not running, apply light pressure to the brake pedal, and then start the car. If the brake pedal falls a couple of inches, the brake booster is working and probably OK.

My quess is that you've got air in your brake lines. You could do a thorough bleeding, but since you'll be installing new braided ss lines, you'll be doing that anyway. Try to minimize how much air you let into the system when you swap lines. It will probably be worthwhile to bleed the brakes, bed the pads, brake hard enough to activate ABS, and then bleed each corner again.