My 08 GS460 has what feels to me like very weak brakes, the pedal isn't very responsive, driving newer lexus' I've noticed they all have much stronger brakes that react instantly when barely even touching the brake pedal, even my girlfriends 2016 Corolla brakes are much stronger and more responsive than mine. I've brought it to Lexus and they say everything is fine. The car still stops ok and its not to a point where I feel like I'll hit anyone but I'd imagine they were much better when the car was new, pads and rotors are still good and dealer didn't notice anything with calipers, is this just normal on 3GS? Or has anyone else felt this? I saw there was a thread a while back about the LS and GS460 brake actuators.

 

Have you ever changed/flushed the brake fluid? Suppose to be done every 3 years as brake fluid absorbs water from the atmosphere.

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When I got my car the actuator was failing and I felt similar to what your describing. I specially felt it when I would press the brake, the pump would start buzzing and my braking felt much weaker than when it wasn't buzzing. After I had it changed braking felt much stronger. It couldn all be subjective but that was my experience.

 

Brake fluid was flushed by Lexus less than a year ago.

 

I saw in a thread that Lexus was replacing the actuator for people but I'm not sure if they're still doing that, my car has no warning lights, and doesn't really make any kind of noise while braking. I do hear a buzzing when I turn my car off for a couple seconds, but I'm not sure if that's the brake actuator or something else.
Sucks because I have a warranty on the car that would cover something like that anyway but Lexus claims nothing is wrong.

 

Any leaks from the braking system? Maybe air was introduce over time. A mechanic that I know a few years back adjust the push rod behind the brake pedal on my '03 Corolla to "increase" the "firmness" when you push down on the brake pedals. Not sure if you could do this on the GS.