Be careful of those coated rotors!

[Hall]

Originally Posted by demarpaint
I didn't think coating the braking surface with paint is a good idea. It seems to me a cost cutting compromise to finishing off coated rotors, they save a few pennies not masking off the braking surface prior to painting them.

I think the issue is that rotors are used on different applications/models but the brake caliper pads might be slightly different.That means on some vehicles there will be paint under the pad area while others will be unpainted where the pad doesn't contact (and will develop permanent rust).

 

[4WD]

I put Callahan slotted rotors (PowerStop pads) on my Canyon … they looked more galvanized - and the discs were cast thicker (air gap smaller … but also drilled/chamfered)
No issues with break in … perhaps the slots helped shed the used coating … Much improved stopping power and no rust

 

[HangFire]

Originally Posted by dan_erickson
I've never had a problem with the Duralast Gold or Duralast Max pads. Anyways, I do not have Duralast pads at this time on my Honda so that's not true

So what pads did you use? Maybe that's the real issue here.

 

[dan_erickson]

Originally Posted by HangFire
Originally Posted by dan_erickson
I've never had a problem with the Duralast Gold or Duralast Max pads. Anyways, I do not have Duralast pads at this time on my Honda so that's not true

So what pads did you use? Maybe that's the real issue here.

Raybestos EHT pads

 

[Balrog006]

Originally Posted by FlyNavyP3
Most of the coated rotors I've ever used were Zinc/Aluminum coated and had no issues, the ones that were painted weren't painted on the pad/rotor interface.



Ditto, no paint or coating on any rotor surface I've used.

 

[The Critic]

Some of those coated rotors have a very rough surface underneath the paint. I recently did a C250 using rotors and pads from the MB dealer (with the factory stuff, not the new value line) and the brakes just didn't feel right at first. The rotor surface still had visible marks. After a few thousand miles, the pads did eat into the rotors to smooth them out.

We usually use the Centric Premium rotors or the Akebono rotors. IMO, the recent Centric Premiums have had a really smooth finish. But they only come painted on the hats and vanes. The Akebono's have been a hit/miss from a finish standpoint, but they do paint the area between the hat and the pad contact surface. Sometimes, I paint the Centric rotors with a Rustoleum self-etching primer (for cars that have a large rust ring) and I have not had any issues during the test drive.

 

[Sayjac]

Rust not an issue here however having purchased/installed the Wagner Ecoated rotors before, some reviews mention non "painted" areas were prone to rust. Those areas are on the rotor surface not touched by the pads, outer and inner edge rotor surface. 'Ime', there's a difference between "coated" like the Raybestos RPTs and the "painted" type like Wagner Ecoated. According to links AZ says Z Clad "coating" supposed to wear off. The RPTs did exactly as stated/shown in the youtube, no issues.

 

[demarpaint]

The last brake job I did that required rotors was close to 2 years ago. IIRC I bought AC Delco rotors, masked them off and painted them myself. They are holding up extremely well from what I saw during a recent tire replacement. Going forward I think I will continue to do the same.

 

[NormanBuntz]

AZ junk. What a surprise.

 

[racin4ds]

I highly doubt it was "paint" and most likely some form of "E" coating or zinc based chem dip. Either way, it shouldn't have clogged up your pads...

 

[4WD]

Originally Posted by racin4ds
I highly doubt it was "paint" and most likely some form of "E" coating or zinc based chem dip. Either way, it shouldn't have clogged up your pads...


Agree … my Callahan rotors did not look painted … seemed to be a zinc rich process of some kind …
I even did long brackish water crossings and not a speck of rust … not even deep in the fins

 

[LeakySeals]

I was performing some rust prevention recently and took some pictures. Notice the rotor. It's a Raybestos coated rotor that has only been on for two winters. Not anywhere close to the protection the stock ACDelco rotor had. I'm going to get rid of them in the spring

 

[HangFire]

I just noticed this while ordering brake parts on RockAuto. Apparently somebody in the industry has already noticed this coated rotor vs pad situation, and created a product to deal with it:

https://www.rockauto.com/en/moreinfo.php?pk=10476208&cc=1430838&jsn=65

"This innovative and advanced friction line has been developed to address key issues such as brake fade, weak braking response, and excessive noise that many pads face when paired with rotors coated with anti-corrosion compounds. PQ PRO brake pads quickly and efficiently remove the rotor coating without damaging the rotor braking surface underneath while perfectly preparing the rotor surface to accept the delivery of the crucial friction transfer film layer required to optimize your braking experience."

Sounds like a thin layer of abrasive grit on top of the pad?

 

[LeakySeals]

I just performed a front and rear coated rotor brake job. I'm not noticing a problem after coating was ground off. I may take a peek in the spring. How would I clean the pads? Straight brake cleaner with a scruffy or a little bit of sandpaper?

 

[HangFire]

If they perform OK after break-in, I wouldn't do a single thing.

 

[HangFire]

OK, I fit HAD to clean the pads, I would try the least intrusive method first, try that for a while, and work up from there. But each time I pull the brakes apart I think to myself "self, I could just do a new pad slap and be done with it."

Some years back when my Dakota was sitting a lot, I sort of had this situation. My calipers froze and after replacing them, the disc brakes/thick pads still scraped noisely and I needed something operational immediately to do truck work. So I sanded the pads on the belt sander, cleaned up and lubed and threw it together, bedded them as best I could, got my work done and bought new pads come Monday morning.

What I found is:
1. Semi-metallic pads sand down remarkably easily and quickly on a 60 grit belt sander.
2. It's impossible to get a perfectly flat, level sanding job on a belt sander.
3. Not quite flat sanded pads still make awful scraping noises on heavily rusted but very low mileage rotors.

So if forced to sand pads ever again (maybe in some TEOTWAWKI situation), I'd take a precision hand lapping approach with adhesive wet and dry on my marble layout block. Which means if the auto parts store is open, I'm gonna skip all that and buy new pads.

 

[UG_Passat]

Never had issues with Geomet-type coating.

That issue is non-existent on Centric Premium (and higher rotors), as the braking surfaces are not coated with their e-coat paint.

 

[dan_erickson]

The autozone coated rotors with that I have had on my car already have surface rust starting to form. Junk.

 

[JimmyM]

I recently bought a set of front rotors for my Expedition. I usually get NAPA's "Premium" uncoated rotors. But this time they had a coating on them. It was like a thin see through grey coating. Like it got some sort of chemical wash that altered the surface. Never a problem. Hawk LTS pads bedded just fine.
However, I got a set of NAPA's Ultra Premium rotors for my daughter's Impala and they were a bright silver zinc-ish looking finish. After a little break-in drive, the coating on the swept area was gone and looked like any other used rotor surface. The brakes work fine.
Although the Akebono ACT1159's I put on leave me un-impressed. Should have gotten the ASP1159s.