As some of you know, I've had some family issues recently that required me to make an impromptu road trip. The only car available for me to do this in was my XJS. It handled the trip beautifully until the return home when I noticed it getting gradually harder to brake. The pedal still goes down fairly easily, but now it is accompanied by a loud hiss and requires a LOT of force to get the car to stop. If I didn't know any better I'd say the noise was actually in the cabin. I'm assuming this is probably a faulty Booster, but is there anything else this could be? I was planning to refurbish the brake system soon, but wasn't planning on replacing this. (Being a broke college kid I can't afford to replace $200+ parts that are already working)

 

My best guess is in line with yours.

The booster diaphragm has given up.

ANy decent "Brake Repair Specialist" outfit can seperate the 2 halves and fit a new diaphragm.

 

On average how reliable are these boosters? Like, would it be safe to just buy a used one? I live in the middle of nowhere right now and the gas to get to a brake specialist+Labor+the diaphragm itself would come to about the same as replacing the Booster entirely