I did the brakes when I first got the car (2006 S60 2.5T AWD), at about 80k miles, with new Autozone Duralast Gold (the mid-grade) pads and rotors all round, and new brake fluid. I think the brakes felt about the same then, which was an improvement from before, so I didn't think about the pedal feel very much and they seemed to function fine. I bedded them properly and gave them some good hard functional checks, all was well. The car was for a family member so I haven't been its primary driver. No complaints from her but now that the car has come back to me (now with about 96k miles) I can't help but notice it lacks that immediate engagement and bite that I like. I want to restore that immediate bite, even if there might not be anything wrong with the system.
I checked my brake calipers, brake booster, master cylinder, brake lines, and caliper spring installation. No visible issues, brake booster appears to work 100%, no signs of fluid or vacuum leaks, hoses in good shape.
I re-bled the brakes using a LF RF LR RR pattern once (before looking up the correct pattern on the forums) then using a RR LR RF LF pattern twice, got no air the second or third time and hardly any (like 1-2 tiny bubbles from the right front caliper) the first time, I doubt that had anything to do with it since there was no change in pedal feel, still takes about 3" before it bites.
Brake Booster checks fine (used this check method):
Maybe I need a new master cylinder?
At the recommendation of a post I read here, I checked my brake caliper spring installation. They all seem fine to me but figured I'd let some experienced MVS guys weigh in. The rears seem to be sitting a little strangely/at a slight tilt (most obvious in the very last picture) and they lack the rubber bumpers that the fronts have, but I remember that's how they were earlier, not sure if they're supposed to have those rubber bumpers like the fronts do or not, or if that would even matter. Pics below.
So my thoughts are maybe replacing the master cylinder will help, or my caliper springs aren't actually good to go? Any and all thoughts/suggestions are welcome, including those that just tell me I'm crazy and the brakes are fine. Thanks all.
Front passenger side spring:
Rear passenger side spring:
Rear driver's side spring:
Front driver's side spring: No pic but looked exactly the same/mirror of passenger side.