95 LSS brake pedal

My 95 LSS has a weird brake pedal of late, when I stop the car and hold the brake, the pedal will slowly continue move down toward the floor. It doesn't go all the way but it's definitely different than it should be. I first suspected a leaking wheel cylinder but found no leaks nor is the brake fluid low. The only guess I can make is maybe the vacuum booster leaking off that might allow the pedal to go further down. Does anyone know what this is and how to repair? Thanks very much.

bad master cylinder, classic sign of it.

bad master cylinder, classic sign of it.


I hope you're right because I can fix that myself. If this is correct, where is the brake fluid going? Or is it just bypassing some piston areas internally. The last bad master cylinder I had let brake fluid escape out the back where it meets up with the vacuum booster and I knew that was the problem for sure. Thanks

I hope you're right because I can fix that myself. If this is correct, where is the brake fluid going? Or is it just bypassing some piston areas internally. The last bad master cylinder I had let brake fluid escape out the back where it meets up with the vacuum booster and I knew that was the problem for sure. Thanks

I had this problem in my '98 Maxima. It should be just leaking internally. The job cost me around $60 and took about an hour and a half to perform on the Max, and I didn't even have to buy new brake fluid (syphoned it out with a hose)! Napa even gave me some $$ for my old master cylinder (w/o turning that in, the new one would have cost over $100). Good luck!

Thanks for the info on the 98 Max, I think the master cylinder is the problem, I put this new or rebuilt on just 2 years ago from Autozone so looks like I'll get a new one practically free. Thanks for the info.