Delaminated brake rotor caused pedal pulse

As it says, I bought plated rotors to keep them from rusting. They came that way. Sounds OK until some flakes off leaving a rough area on the surface on the rear rotor.
Anyone else see this problem?

brake rotors don't seem to be as good as they used to be. We've put Zimmermann coated rotors on a few cars recently and they just don't last.

Rotors delaminated

vwdsmguy said:

As it says, I bought plated rotors to keep them from rusting. They came that way. Sounds OK until some flakes off leaving a rough area on the surface on the rear rotor.
Anyone else see this problem?

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I saw the same thing with the rotors I bought 3 (or so) years ago from Auto Zone.
Don't recall the name.
My original rear brakes lasted 140K miles (US) the fronts 190K (US)
I do mostly high way driving.
I got the premium rotors & ceramic pads this time, not the basic ones.
It took almost 2 weeks before the pads were broken in.
Every trip I was feeling the rotor temperature when I parked.
One side or the other was a bit hotter then the other or even the fronts.
Seems OK now.

Just my 2 cents (US)
Rich W.

vwdsmguy said:

As it says, I bought plated rotors to keep them from rusting. They came that way. Sounds OK until some flakes off leaving a rough area on the surface on the rear rotor.
Anyone else see this problem?

Click to expand...

Surfaces are NOT treated for rust prevention! Think about, WHY? Rotor surfaces will always show up some slight surface rust if left to sit with moisture. As soon as you apply your brakes that rust is wiped off.

Along with separated brake pads my front rotors (after purchased; and, likely, owing to my efforts to resurrect them) looked like this:

https://www.dropbox.com/s/614kj63t1xky4mc/P1100726_scaled.JPG?dl=0

My Zimmerman rotors are holding up perfectly well now after about 15k miles and 7 months or so. With Akebono pads this is the best feeling braking setup that I've ever experienced.

delaminate - divide or become divided into layers.
This? rotor shouldn't do that.

Often wondered why a company doesn't offer stainless steel rotors. Most parts vendors already offer a cheapo rotor and a higher quality one of most applications.

[486] said:

Often wondered why a company doesn't offer stainless steel rotors. Most parts vendors already offer a cheapo rotor and a higher quality one of most applications.

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I think it's a heat transfer thing, stainless doesn't transfer heat as well. I know a read a reason for not using stainless once. Regular old gray cast iron has the correct properties needed.

RacerTodd said:

I think it's a heat transfer thing, stainless doesn't transfer heat as well. I know a read a reason for not using stainless once. Regular old gray cast iron has the correct properties needed.

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in machine tools it is because of dimensional stability and vibration damping

but really, I'd be willing to have squealy brakes that didn't rust solid after a couple months of sitting

I just put coated rotors on last week. The gray coating is supposed to come off in the first braking instances which should be part of the break-in period.

After that break-in the rotor appears to be bare steel but supposedly also has friction material from the pad adhered to it. The part of the rotor where the pads don't hit stays coated for.... a little while but eventually will also rust.

I've never heard of plated rotors where the plating is meant to be permanent.

the approximate break-in procedure is to do several stops from relatively high speed, to an intermediate speed but do not stop. Keep driving for a few minutes to let the rotors cool and then repeat. You want even heating around the circumference of the rotor as much as you can get it. Hopefully you have a secluded road to drive on.

mk3 said:

I just put coated rotors on last week. The gray coating is supposed to come off in the first braking instances which should be part of the break-in period.

After that break-in the rotor appears to be bare steel but supposedly also has friction material from the pad adhered to it. The part of the rotor where the pads don't hit stays coated for.... a little while but eventually will also rust.

I've never heard of plated rotors where the plating is meant to be permanent.

the approximate break-in procedure is to do several stops from relatively high speed, to an intermediate speed but do not stop. Keep driving for a few minutes to let the rotors cool and then repeat. You want even heating around the circumference of the rotor as much as you can get it. Hopefully you have a secluded road to drive on.

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You're supposed to clean off the gray material from the rotor facing before installing. At least that's the info that I'd had.

Yes, proper break-in is key. With my Akebonos I went the full range, just to eliminate ANY doubt: they said something like 3 to 5 sets at different speeds; I went the full number of sets: I'd lived with crappy, pulsing brakes on Toyota, and after getting my Golf and find that it's brakes were also crappy I was really not happy, I was determined that I was going to have nice brakes! It's a bit nerve-racking to do, getting a roadway that you can attain the necessary speeds with a light enough traffic level to be nearly stopping (slowing down) to low speeds. After about 15k miles the wear on the rotors looks imperceptible- I chalk this up to having followed the break-in procedure to a "T."

Interestingly, the break-in is supposed to (evenly) DEPOSIT brake pad material on the rotor's surface!

I just finished installing a set of the z-coated Zimmerman disks, and the information card included in the box states not to remove the coating. It's designed to rub off during the first few stops.

like many things on the internet there are opposing answers.

one is here:

http://www.otto-zimmermann.de/en/produkte/coat-z-beschichtete-bremsscheiben.html

I am not sure if all 'gray paint' coatings are the same. One source stated the coating is just zinc paint. That makes a lot of sense.

I did remove some paint from the back side of the rotor where it would contact the hub. There wasn't much there but I was trying to be extremely thorough in the hopes my rotor would run straight.

If you buy rotors without gray paint or other dry coating they will be oily. The oil does need to be cleaned off before you drive them.

I don't recall whether the instructions that I had said to leave the coating on or not. If they say it's OK to leave it on then that's just one less thing to have to hassle with. As long as one doesn't remove more than just what's on the surface then it's not hurting anything (other than using up brake cleaner and time).

Both my rear rotors have a rough, heavy rust on the outer surface. I checked the right side caliper twice and regreased the sliders. I also rebled all four lines, but the problem is still there. I purchased the rotors a few years ago from one of our vendors. I can feel the roughness when I brake hard.

Who uses their brakes?

Less braking=Better MPG

I haven't had much problems at all with brake rust. Though, I don't let my vehicles sit long without driving them. (2 weeks tops)

Oh and I use cheap Carquest rotors

However, I did put copper anit-seize on all of the slide pins to keep them from getting sticky in the future

You're in TN, you see humidity, but not 6 months of saltwater every year.

JB05 said:

Both my rear rotors have a rough, heavy rust on the outer surface. I checked the right side caliper twice and regreased the sliders. I also rebled all four lines, but the problem is still there. I purchased the rotors a few years ago from one of our vendors. I can feel the roughness when I brake hard.

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it's because rear brakes don't do much, so they don't knock the rust off the rotors as quick as it forms

one of the huge advantages of rear drums is that they're enclosed and do not rust up a quarter as fast

Here's an update. I tried to wire brush and scrape off the rust but discovered that I have the same problem as the OP. The outer surface of the right rear rotor is just flaking off. I plan on sourcing my replacements locally from now on. These are three year old rotors from one of our on-line vendors.

I bought the Autozone Duralast 34143DG for my wagon. It appeared the were painted. The instructions said leave the coating alone. It came off in the first application. The brakes work fine.

JB05 said:

Here's an update. I tried to wire brush and scrape off the rust but discovered that I have the same problem as the OP. The outer surface of the right rear rotor is just flaking off. I plan on sourcing my replacements locally from now on. These are three year old rotors from one of our on-line vendors.

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All of them will rust up like that, and nobody will warranty for it.
Be a lot harder on your brakes and they'll scrub the rust off as it begins to appear. Takes a bit for the rear to get any pressure through the proportioning valve, if you brake like a grandma all the time it is only the fronts doing anything.