Removing pad deposit from brake rotors

I somehow heated up the pads enough to have some leave a brakepad shaped imprint on the front left rotor of my celica. This didn't happen from the 4 track days I've done on the brakes, and I don't remember doing anything stupid on the street-other than maybe trying to get an air bubble out of the abs system. It hasn't bothered me enough to address it but I have a track day early april. Rotors have probably 10k miles and look fine no cracking otherwise. Pad is a stoptech sport/309.
 

1. Try rebedding the brakes (will this melt my winter tires? the stoptech procedure is 10 x 60mph-10mph stops)
2. Take the rotor to get it turned (Is this done anymore? how much does this usually cost)
   • Steel wool?
3. New rotor (Can I get away with replacing 1?)

I'm trying to do fix this as cheaply/easily as possible, but the cost savings is more of a mental barrier than anything. Leaning towards rebedding and if that fails to just replace the rotor on one side
If need be I'll pony up for whatever needs to be done, but I don't want to spend/waste money unnecessarily either.

a deposit as in you can feel something on the rotor when you run your finger over it?

I'd re-bed them. 

I jack up the car,   Take the wheel off, then with a wire brush on my side-grinder I scrub both sides of the rotor with gusto.  Then put the pads back in and bed them per regular instructions.

For good brakes to work really well some of the pad material gets embedded in the rotor.  So if you are drastically changing pad formulas this is a good plan.  So the rotor has material embedded that matches the pads.

YMMV

l5weolvsf: When I had my summer wheels on, I could see an outline of the pad on the rotor. Hadn't felt it and can't with steelies with the wheelon

Purple Frog: Could this cause high and low spots in the rotor if I hit it when the wire wheel/brush? I figured if I were to pull the rotor and wheel I might as well just slap on a new rotor and save a little bit of headache and guesswork. I'm not completely against this since it's not that much work.

chandler: I was just on my way out 10 minutes ago and unfortunately it rained sometime in the evening. I'll have to wait until after the weekend to give it a shot.

That's not abnormal. If you are not able to feel it through the steering wheel during braking, Id say send it. 

"Pad deposits" are the cause for pulsing through the peddle and wobbly steering wheel. If it's just a visual outline you might be fine. 

Just rebed them. If you can't feel the high spot, that's all you need.

No pulsation? No worries.

This is nothing unusual, it's just the first time you noticed it.

If you can't feel it you can safely ignore it, if you can feel it or if it bothers you too much, Purple Frog's procedure is a good one.

I always try re-bedding first.

Turning rotors was something they did up until the 80s/90s but it has declined big time.  Newer metallurgy lets them make rotors lighter and thinner, so until you machine them, they're thin enough that they'll likely warp in short order.  Back then it was $40 to buy a thick-cast, US made rotor and $8 to turn it on a lathe, so it made sense.  These days you'll be lucky to find someone who turns rotors at all, and new overseas rotors are probably $20 on Rock Auto.

Turning them on a lathe also doesn't leave an ideal finish

Totally fine to use a new rotor on old pads

Supposedly one way to do it is to install some super aggressive racing pads that are known to eat rotors (Hawk Blues, for example) and go drive the car hard enough to clear those deposits off the rotors, but not hard enough to bed the Blues.

https://www.brakes-shop.com/brakepedia/pads/uneven-pad-deposit-removal

No personal experience with this though.

In reply to codrus (Forum Supporter) :

I've done it with some $18 FLAPS metallic pads.  Works ok.

But again... rotors for my van are $22.

Curtis73 (Forum Supporter) said:

 These days you'll be lucky to find someone who turns rotors at all, and new overseas rotors are probably $20 on Rock Auto.

I wish. Fronts for my BMW are a couple of hundred each!

wspohn said:

Curtis73 (Forum Supporter) said:

 These days you'll be lucky to find someone who turns rotors at all, and new overseas rotors are probably $20 on Rock Auto.

 

I wish. Fronts for my BMW are a couple of hundred each!

Not sure about the maple/hockey tax, but Rock Auto has Z4 rotors for as little as $22.79, the bigger 325mm are $32 USD, unless you want the carbon-ceramic.

Rock Auto Link.

Well the backside of the rotor has a pretty significant lip so they're due for replacement. Pads are at ~8/17mm. I guess I'll bite the bullet and get a new set of pads & rotors. I'm pretty upset that the 309s went from $55 to $85, but still cheap for what they do.

I've had good luck with the bosch quietcast rotors (these are acutally 6 years old), but prices went up and I'm going to roll the dice with power stop evolutions this time.

I've never used the Evolutions, but I have used plenty of powerstop's HD stuff on my trucks and I've been happy.

Brake rotor thickness limits is mostly to prevent the caliper piston(s) from overtravel when the pads are worn out.

I have had brake rotors .125" thinner than minimum and everything was fine.  If they pulsate when hot, they will do it whether in spec or not, as it is mostly a function of core shift during the manufacturing process.  Newer brake rotors are built to far better standards than older ones.

I don't even measure mine, I just trim 'em assuming I can't just slap new pads on.  On teh Volvo with its 330x32 rotors, I figure it is the same calipers and rotor blanks as the umpteen zillion other cars with 330x30, so making the rotors thinner means I can use pads made for an STI or Evo instead of being stuck with S60R specific parts 

I use an angle grinder with a flappy disc.  Doesn't really remove material, but will get thise spots off the rotor.

You can do it without removing the disc and it actually spins the disc at the same time.

So much for doing it cheap. I just slapped pads on my rears last summer, but I figure I might as well prep the car right if I'm tracking it. Ordered a full set of pads/rotors. I miss 2017 prices for parts.

Did you drive it in the rain, then park it wet, for a few days?  That looks more like a ring of rust on the small screen.