Resurface Rotors from re-bedding?

Hey all I want to share my experience with my wife's new 4runner. We purchased a used SR5 5th gen and one of the first things she complained about was the vibration under braking. The pads were 60% and rotors looked pretty good, no excessive grooving. I've had frequent vibration issues with my old Subaru in the past and noticed a pad "spot" on the rotor from it either, sitting for too long (salt doesn't help), or parking with heat soaked brake pads. I used to think theses were warped rotors, but from what I read, that's pretty uncommon now a days with rotor technology for them to warp, and, if they were warped you would feel pedal pulsation. Her 4runner vibrations were not in the pedal but rather in the whole car itself.

Recently, before her 4runner, we towed a 2k trailer cross country for our wedding in her crosstrek. Since it was pretty much at the towing capacity and we were going to be going through the mountains, I decided to upgrade with some drilled and slotted rotors to prevent brake fade. When I purchased the rotors they came with "bedding" instructions, which I had previously never heard of before. its pretty much transferring material from the pad to the rotor surface or "bedding" the material. I'm a pretty big car person and couldn't believe I had never heard of this process before.

back to the 4runner, before going out and buying new pads and rotors, I decided to to some research on the bedding process. This led me to some enthusiast car websites where it sounds like vibration is common at track days from heating up the pads, heading to the pits, and letting the hot pads sit on the rotors, then experiencing vibrations while city driving. Many people mentioned that after a couple more hot laps back at the track, the vibration would go away.

I noticed that her pads had the same pad imprint on the rotor that I've seen before. After my new found knowledge of bedding, I thought maybe this is just access pad material on the rotor. So out of curiosity, I went out last night in her 4Runner and completed the bedding process with doing 5 60-10mph moderate to aggressive stops followed by 5 35-10mph moderate stops. Then, drove without coming to a complete stop for about 10 minutes to let it cool down. I must say, the vibration is significantly less (she even agreed today). Although it is not completely gone, this somewhat verifies my theory that it was the excess pad buildup instead of a warped rotor and I was able to "resurface" the rotor with the bedding process. I can also hardly see the pad imprint on the rotor now. I'm going to try this process again today and see if I can improve more.

Like I said, this is not exact science, but brake vibrations are very common, maybe it can save you guys a couple bucks in the future.

oh, and here is his and hers, just for kicks

 

Sounds like your wife "drives the 4-Runner hard, and puts it away wet." Just ask her to ease off the heavy braking several miles from home...lol

 

lol, well, the brakes were like that when it came off the truck. Not from her.