That's where I've been coming from with this from the word go, simply because it just seems like too much of a coincidence that this started when it started. For a while I had myself persuaded I had a sticking caliper but now I'm not sure. Deep down, I still think there must be something causing friction where there shouldn't be friction. Could something as simple as corrosion around hubs (or discs or whatever) cause this? Maybe if the car is on a ramp for a while things settle in a different position, but once the wheels are bearing the load for any length of time they revert back again?
I'm getting my girlfriend to drive the car home this evening to see if I'm crazy. Of course, given that I'm letting her drive, I *must* be crazy...
Si
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Corrosion on the disk faces (ie the braking surface) would be a symptom, not a cause of a sticking caliper. It's possible that an excess of corrosion not on the braking surface could interfere with pad operation, but I doubt that's your problem.
Are all the faces (both sides of each disk) nice and clean when you've been out for a run?
If you put it on jacks/stands, do the wheels spin fairly freely?
Also is your handbrake OK - this operates a separate brake mech' on the inside of the rear disks. I've had problems with this setup on other cars due to poor servicing (not Lexus).