Warped rotors again.... AC Delco slotted rotors?

Hey everyone. So I had these brakes replaced all around about 3 years ago and I believe the front rotors are warped again so I am in the market for a new set of rotors and pads as I am getting pulsation and vibration hitting the brakes from higher speeds. Would like to stick with AC Delco so I started looking on RockAuto and Amazon. Noticed these slotted ones actually made by them and marketed for heavy duty. Anyone ever use this specific model before and are they really that good? Looking for a combination with improved stopping distance that isn't going to warp as easily. I have never had pads replaced before on either of my truck which were low unless it was a caliper failure or warped rotors. Also with 64k, maybe also time to have the calipers and rubber lines replaced? What are the best brands for those if not also AC Delco? Thinking back from experience with my old truck eating calipers. Thanks

Pads: 17D1169CH https://www.rockauto.com/en/moreinfo.php?pk=1021662&cc=1433505&jsn=534 for front and 17D883CH for rear https://www.rockauto.com/en/moreinfo.php?pk=678335&cc=1433505&jsn=535

Rotors: 18A1756SD https://www.rockauto.com/en/moreinfo.php?pk=8365872&cc=1433505&jsn=606 for front and 18A1207 https://www.rockauto.com/en/moreinfo.php?pk=452073&cc=1433505&jsn=593
I've got 265,000 miles on my ext. Personally, I like the ac delco rotors, I've used a few varieties and they just seem to last the longest. Not the "advantage" ones mind you, those are delco cheapos.

Whatever rotor you use, these vehicles seem very prone (at least mine is) to warping rotors if things aren't perfect:
- grease up your caliper slide pins on a regular basis, like when you rotate tires.
- if you use anti seize, be very judicious on the stuff you use on the rotor/hub area. GM even has something in their service manual about too much causing rotor warping
- tighten your lug nuts on the cross method, and use a torque wrench to make sure they are similar. I think uneven tightening can cause rotors to warpen as much as too much.
- if new brake pads, bed them.

Those slotted ones you see by AC Delco I have not used yet, but if I were buying rotors I would consider them.
Just search for @Chickenhawk 's posts about slotted/drilled rotors. His experience speaks volumes and would take his advice of buying Adaptive One pads and rotors. A close second would be ACDelco's Pro pads and rotors (not slotted).

Don't know what year TB you have (your profile says 2010 which doesn't exist), if you don't have the larger front brakes which came on all EXT and V8 trucks, you should swap out to those. Very easy. Just need the brackets.
Thanks for the kind words everyone. I tend to be serious about brakes, shocks, suspension and handling balance. (Getting to test police cars on race tracks for what my wife laughingly refers to as part of "a living" does that to me.)

To summarize, my views on slotted and drilled rotors are that they are only for looks. They do not improve braking and there isn't one bit of scientific evidence to prove that they do. They use a lot of "junk science" to say they improve cooling, etc. even when it is physically impossible for air to move in a way they suggest. If people want them for the looks, then go for it. Well-made drilled rotors are not that much worse than a well-made solid rotor, and any new rotor is better than an old, worn one. (No one cuts rotors these days. New ones are cheap and available everywhere.)

My experience with a slotted rotor did not end well. Because I live in Canada, there is salt on the roads in winter, and all that rust got into the slots and the entire polished braking surface started de-laminating badly, starting from the slot and rusting UNDERNEATH the polished surface. The rotor was left with about 20% of the surface actually used for braking, and the rusty surface left behind tore up my pads in short order.

If you live where rust is a problem, I would suggest staying away from slotted rotors or drilled and slotted rotors.

As my friend above suggests, one can never go wrong with solid rotors from the AC Delco "professional" line. (The "advantage" line is their economy line.) I have also had good results from the NAPA ultra premium rotors, and the coating stayed intact for years.

Mine will be due in another year or so, and I will stick with either the NAPA Adaptive One pads (depending on how they look when I finally take them off) and ultra premium rotor, or the coated AC Delco professional rotors and professional pads.

The reason I like the Adaptive One pads is because of the backing of the pads to the plates. They use a special hook-like backing plate similar to the NRS brake pad backing system that really prevents the pad from peeling off the backing plate down the road.

The Adaptive One pad also features a harder compound on the outside pad to reduce dusting on the wheels. It will be interesting when I take them off in a year or so to see the difference in pad wear inside-to-outside.

Note: Many 360 platform vehicles have different wear rates on the inside pad versus the outside. It is normal. As long as the pins are properly lubed when installed and the pins are in good shape, wear differences do not always indicate a problem.

smt 59

Well-Known Member
All great information here, I purchased Brakemotive drilled and slotted rotors about 3 or more years ago for the Voy and they have been great and still working fine. They are now sold off of EBay with good pricing. I live and drive in the road salt capital of Canada(Toronto and north) and I have not experienced any issues with rust or delamination of any kind. I am also very hard on braking as I run the DVP, 400 and 401 for those of you familiar with these parts and still show no signs of warping.

Just my 2 cents worth.
I agree that Brakemotive makes good rotors. (I think the pads in their packages are not as good quality as some of the other pads on the market, though.) Brakemotive is an example of what I say about a good drilled and slotted rotor being almost as good as a good solid rotor. And, of course, a good drilled and slotted rotor is way better than a bad rotor of any kind. Just don't expect any improvement in performance when comparing new drilled rotors to new solid rotors. It is just for looks.

And, Lord knows, we all do a lot of stuff just for the looks.


Well-Known Member
Just an FYI:
I've had rotors tuned at O'Reilly Auto Parts. $20 for the two front rotors. (Total price. Not each rotor)

smt 59

Well-Known Member
I agree that Brakemotive makes good rotors. (I think the pads in their packages are not as good quality as some of the other pads on the market, though.) Brakemotive is an example of what I say about a good drilled and slotted rotor being almost as good as a good solid rotor. And, of course, a good drilled and slotted rotor is way better than a bad rotor of any kind. Just don't expect any improvement in performance when comparing new drilled rotors to new solid rotors. It is just for looks.

And, Lord knows, we all do a lot of stuff just for the looks.

Agreed, they do look good!
Problem with turning warped rotors is that they will probably warp even faster with less material to dissipate heat. That being said, if your existing rotors are still good and not warped, nothing wrong with just replacing the pads.


Well-Known Member
Wow I didn't think I was going to ignite such a nice, well discussed thread but after all this is a hot topic... This is great.

Thanks everyone for the very useful information here, I think am going to find the top AC Delco or best aftermarket stock solid rotor I can find, maybe the Professional ones that have a painted hub and cooling vanes (I have OE on the front and Advantage on the rear at the moment, those have to go.) and stay away from the drilled/slotted ones, especially as I do live in a very rusty state of NY only a couple hundred miles south of Canada and the way I hit these brakes from high speeds a solid one would be in order. The EXT brake mod I have considered, the problem is no shop around here would want to make modifications on that.

Also does Raybestos make AC Delco parts? I couldn't help but notice the photos between the two brands in several places look almost if not completely identical. I was also checking out the Advanced Technology ones and the best pads I can get while keeping it stock.

Also what brand calipers should I consider and the rubber lines would be in order at this stage correct? Keep with AC Delco?

Sorry about the 2010 model year, I will fix that. The truck is a 2007.

Thanks again
Also does Raybestos make AC Delco parts? I couldn't help but notice the photos between the two brands in several places look almost if not completely identical.
I have long been suspecting that they are made by Raybestos with the same conclusions as you.

The EXT brake mod is barely a mod. Replace the caliper brackets and use EXT rotors. Rest of the parts stay the same. However, you have an '07, like mine. It may have the bigger brakes already but I have to do some comparisons between my 9-7x with the V8 that does have the bigger brakes and the '07. It seems to have the bigger brakes because the cooling vanes are the same but haven't made actual measurements of the rotors. And the 06+ use cast iron calipers whereas the older ones use aluminum and different brackets, like on the EXT. Either way, you can't do the EXT mod.
Out of curiosity, I checked price /availability for pads for my '12 Acadia. What a huge difference in pricing on both sides of the border. Napa US price for pads is $65.00 front or back. Napa Canada is $155.00 front and $145.00 rear. WOW.


Well-Known Member
I've wondered about the whole warped rotor myth and have felt the pulsation of what you would call 'warped'. To get a pulsation you need to have the rotor pump the oil back to the master to feel the pulsation. I just don't see it happening. What has been suggested and I'd be more inclined to believe it brake pad material being deposited under high heat/speed to the rotor face. That wold certainly cause a warped feeling. I had an Oldsmobile 98 with cheap pads that would 'warp' on a certain off ramp from 75 reliably. After they cooled off I would stomp on them to clean them off. Since then I typically buy chepo rotors with premium pads. Again, just my opinion.

Found an article that suggests in the authors opinion much the same idea HERE.


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Funny that I was looking for pads / rotors for the HD Sierra, and ran across this in 'new' posts...

- @ComputernerdBD - those AC Delco slotted rotors you ask about are definitely Raybestos sourced. You can see in a side-by-side from both a photos & specs comparison. They're available for my HD, but I'm going with something different, myself. No knocks on Raybestos - those NAPA Adaptive Ones are theirs as well (more on these below).

The advice you're getting on the EXT / XL rotors along with the A1s - I have them, and second (third? fourth?) that recommendation - heartily. NAPA sells two front kits for the LWB, both with the A1s - $200 or $170, depending on whether you want their best / second best rotor. For some reason, I can't log on to my NAPA account to check on which ones I bought for the Voy (& NAPA won't send a p/w reset email to any of the 3 accounts I would've used for it). I'm guessing I bought NBK 7759ADK2C , which has the 'Ultra Premium' rotors, but NBK 7759ADK2 has the 'Premium' rotors and is $30 cheaper. My rear rotors are rusty, so I probably went with the slightly cheaper rotor there. And as @Chickenhawk described in an earlier thread (which I saved to my hard drive, and still refer to) - you don't need to go all spendy on the rear. The fronts are where the money goes :smile:

Get one of those two kits above, the LWB brackets, and your front brake search is over. The Adaptive Ones, once properly bedded in, are THE best pads I have ever had occasion to install / use on a regular 'consumer-level' (non-competition) vehicle. Full stop.

After installing mine, I had to adjust my braking style with the Envoy, as I was stopping about 10-20 ft *too short* behind traffic at the stoplights. Yet they're not excessively 'grabby'. They're good enough that I consider my Prodigy trailer brake controller more or less a 'wasted' purchase - I trust them enough to stop the 10,000 lbs of me and trailer, alone. Even in the mountains. If I still had my track toy, and these brakes were available for it (they are!), these would be on it, at least for evaluation.

No, I don't work for NAPA! And I will admit - I drive conservatively, off-track. So if you're a more aggressive driver, your experience will be different. The Envoy doesn't have the new safety goodies (autonomous / automatic braking, collision warning, etc.) - so having the extra stopping margin, should I ever need it, is peace of mind.

As far as warpage of the rotors - if you're getting good quality rotors (material & thickness), and not unevenly / over-torquing them, then warpage shouldn't be an issue, I would think - ? If a shop has been putting them on for you, it's time to confront them on it, so they can pay for the replacements. There's no excuse for putting the gun on the lug nuts at full power, just because it's easy / quick.

Calipers and hoses - I'd leave those alone (replace stock-for-stock, and only as-needed), on a street-driven 360. Off-road, you can do whatever you feel necessary. :cool: If you're worried about the calipers not releasing, take the truck in and have it checked out (Firestone, as an example, does a very nice $10 'full vehicle inspection'; the brakes / calipers are included in that $10). Just be aware that shops can use the inspection as a loss leader - to help sell parts & services. But having a professional inspect them provides peace of mind, as well as liability protection, should the worst happen out on the road. Can save money in the long run, too (by retiring the parts shotgun). :thumbsup:

I think that covers most of what you asked about. If you do decide (need) to replace calipers / hoses - use the same type of caliper, whether single- or dual-piston, etc. Otherwise, you're compromising the engineering of the OEM system, even if you go 'better / bigger')

Stainless (especially braided stainless) hoses *look* nice, but unless pure appearance is a factor, the rubber ones are generally fine for consumer applications. If there were an issue with them, the OEMs would have switched to something different by now, either by desire or force.

One more thing - if the brake fluid is factory fill, or you don't know when it was replaced last - take care of that during your next brake service. It can be a PITA to do it alone, but you can rig up a self-bleeding system with some clear tubing & an empty Gatorade bottle (videos a-plenty on YT, so I won't go into details). If you have a helper to step on the pedal for you, it becomes child's play.

Finally...For anyone wondering what I'm choosing for the Sierra - it turns out that there is no NRS / NUCAP front pad option for that truck (at least, available at the 'consumer' level). :eyebrowhuh: That hurts. But I'm not going to use 'fleet' or semi-metallic pads (see: my earlier comments above on @Chickenhawk's recommendations)

After spending last night & part of this morning looking at options (yeah, I'm that anal...lol), I'm likely going with AC Delco 'Performance' ceramic pads all around (again, likely a Raybestos re-branding), along with Bendix 'Severe Duty' (Fleet / Police 'MetLok' spec) front rotors / Raybestos coated (anti-rust) rears.

This looks like a good price / performance mix; if it turns out I find a weak component, I can replace it without worrying about having wasted a ton of cash finding out. The Sierra has RPO JH6 - 9900 lb disc brake - so it gets a big beefy rotor & pad combo to begin with.

E.g.; I should be fine, even if I upgrade the trailer at some point and pull at / near max GVWR. :yikes:

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