More problems now.

... the chief reason being to get the rotor back on with minimum lateral runout. Sometimes, thanks to salt and rust, the hub and rotor faces might not be quite flat any more, and they probably match each other best in the way they were sitting. Notice the spiffy tool used in this video to clean up the hub face of rust around the studs and the centering ring. (Of course, that face on the inside of the rotor should be cleaned up too.)

If you didn't mark the rotor's original position, it's not a problem; there are just five ways to put the rotor on, and if you measure the runout for each, usually one way will turn out to have less runout than the others, so that's the one you use. That's the real point of the exercise; remembering the original position is just a shortcut that usually works. (What if somebody had the rotor off before you, and didn't put it back in the least-runout position? If you just try all five ways and pick the best, you'll still get it right anyway.)

Putting on a new hub changes things anyway (because its face will really be flat), so then you just want to clean up the rotor face as close to flat as you can (if you're not replacing that), and again, just measure the runout when putting it on, and use the best position.

Random notes on the video: (1) we don't need special spacers under the lug nuts to snug the rotors for runout measurements; the standard Toyota nuts (with the captive washers for aluminum wheels but also cone ends for the spare) are deep enough to do the trick; (2) impact wrench just to snug the nuts for a measurement? really?? (3) the video suggests 0.003 inch as a limit for acceptable runout, but Toyota's standard is 0.002 or less.

-Chap

 

With a flat new hub and flat new rotor, there's a decent chance you'll measure 0.002" or less of runout in the first position you try, so then it's up to you whether to still try four more ways looking for the very best, or just call that one good enough.

-Chap

 

Shocking. That'll make you the first person in history to reassemble brakes without measuring your runout. What is the world coming to?

And probably it'll be fine, and if it isn't, or you notice vibrations, pedal pulsations, or noises like this when you stop, you'll know what to go back and do.



-Chap

 

A dial indicator with magnetic base is a handy thing to have, good Xmas present lol.