Revets00

One day at a traffic light I noticed my brake petal slowly sinking to floorboard. I replaced it with new master cylinder. One week later started doing same thing. They replaced it and I installed another new master cylinder. Now the same thing. I bench bleed the cylinders and bled all four wheels when installing. Took off all wheels inspected wheel cylinders and found no leaks. I have no brake warning lights showing in the dash. I'm not losing brake fluid anywhere I can tell.
Also I did not see any fluid leaking into the brake booster when I pulled the master cylinder.
I don't know the problem but I am getting good changing them out.

05RX330AWD

From the 05 Lexus RX330 Repair Manual:
If you need more info, let me know....

5W40

May still has air trapped in ABS Actuator ,Try ABS bleeding screw or use Techsteam bleeding ABS Actuator.

numbafree

I got air in my lines once, didn't realize the reservoir hose was on the side, not the bottom. The only thing that got the air out of the lines (and a lot of brake fluid) was:



power bleeder. I don't actually put BF in the container, I just stop and refill the res. 8-10 psi is all you need pump the brake pedal 3-4 times gently, each time to get the air bubbles out, and then crack the bleeder screw just of a few seconds. close and repeat. You can re use the new BF if your catch container is clean.

Since I first bought the power bleeder, I've used it several times on friend's cars and motorcycles for normal bleeds and to get air bubbles out of the lines.

good luck.