I had a brake problem that is probably due to my master cylinder being bad or air in the lines or old brake fluid. I was putting off repairing it because my brakes were fine. I went somewhere and parked my car. When I came back from doing things, my brakes barely worked. I had to go on back roads with my emergency lights on to get home without a tow. Anyhow, when my car was off, it passed brake booster tests that people have put on line. It was firm when the car was off but went to the floor when the car was running. Now it sinks in to the floor when the car is off with an added sound towards the bottom of depression and a sound when I release. I recorded a video and it shows a white object going in and out along with the brake pedal. I'm worried that it is part of the brake booster and now I need to replace that as well. I don't have any software to edit an arrow into the video, but it's attached to the bar that is attached to the pedal. It seems like that part should not be sinking in. Using my ability to guess what my christmas presents are, it feels like rubber of the brake booster is giving in and folding over itself. I'm hoping someone will tell me what I want to hear and say that I don't need a new brake booster as well as a new master cylinder. But since that's likely what I'm going to hear, is there a substitute for the VW brake tool to attach a new power booster to the brake pedal?