Noise under dash when moving brake pedal

[Bip35]

2004 Ranger Edge 2.8 Auto. 52,000 miles. Brakes work great, but there is a noise coming from something under the dash. I can push the brake and hold it in one position. If I let up or push down from this halfway position, I get a noise as if the linkage under the dash needs lubricating. I sprayed WD-40 on all the linkage I could find. The sound is like a dry rubber gromet is trying to slide on a dry shaft. Any suggestions? Anyone had this noise? Any help would GREATLY be appreciated. Ron

 

[hondaxr650]

Yeah, I've seen that before. It was the brake booster itself. No amount of lubing helped. Replacing the booster solved the problem.

 

[Bip]

Is my Brake Booster going bad? Is it going to fail? Or can I just put up with the noise and not worry about it?