[tj0007]

Rear pads are worn down on my 1995 Concours so I bought a set of pads from Advance. I have the rear brakes all taken apart on the driveway, and notice the rotors aren't perfectly smooth(can feel slight difference when running finger across them). So I called Advance to see if they stock rotors and no stores had them or could order them. Next I looked up the rotors on Rock auto and see that there's an AC Delco rotor listed in the "economy" list for $17.79 each (p.n. 18A488A), and another AC Delco rotor listed in the "heavy duty" list for $29.79 each (p.n. 18A488). Both list the same dimensions, but the more expensive rotor says "supplied in o.e. noise dampening iron", and the cheaper one does not. Other than that, the only difference is the more expensive rotor has a black coating on the center.

Are both these rotors actually noise dampening iron but the cheaper ones just don't say that? Does this 1995 deville/concours need it to be noise dampening iron? I'd just like to put on the direct o.e. replacement if I'm going to order online anyway.. and even the $29.79 price rotors are affordable for me right now. BUT which are stock?

If it matters.. the brakes on the car were working but starting to make noise because pads wore down. Parking brake works and I use it every day. just hit 100,000 miles.

 

[Submariner409]

I'm not gonna touch "noise dampening iron" with a 50 foot pole. Marketing hype. Get the best rotors you can afford.

You can take the rotors to a decent Mom&Pop shop - ask them to measure the thickness - if it's within limits the present rotors can be skimmed - restore the dead flat surface - and used again.

Clean the hub, rotor, and wheel mounting surfaces and torque the lug nuts sequentially to 100 lb/ft in a star pattern.

 

[Ranger]

"Noise Dampening Iron". :histeric:

I am of the other opinion. Rotors are rotors. They are all made of cast iron (in China). The cheapest should perform the same as the most expensive (assuming the same dimensions). I really don't think you are gaining anything by buying expensive rotors.

 

[tj0007]

Well I'm stuck without a car for now, and the nearest shop is like 10 miles away.. so instead of driving back n forth to have em turned down I was gonna order the new rotors online and just wait for them to show up to finish. I work a mile from home so I'm use to riding my Chevro-legs.

Do you think there would be any noticeable difference between the two different AC Delco rotors' material? I mean, this is AC Delco's own description of the two rotors, not some auto store slogan. But they do have different part numbers...

 

[MoistCabbage]

Metallurgy differs slightly between twits of rotors (nothing to do with noise damping...), but the main difference will be in precision of machining (how true the rotor is mostly). The other difference, as you've seen, is a rust preventative paint on the non friction surfaces.

 

[drewsdeville]

I am of the other opinion. Rotors are rotors. They are all made of cast iron (in China). The cheapest should perform the same as the most expensive (assuming the same dimensions). I really don't think you are gaining anything by buying expensive rotors.

This.

Stock is roughed out mostly (if not all) overseas. It's purchased by and shipped to various finishers around the world who paint, galvanize, cut, drill/slot, finish, etc the roughed units. They are then marketed appropriately.

They are all equivalent, and last the same amount of time when given the same treatment. Nowadays, I shop by corrosion protection and seek out galvanized units vs bare, painted, or fancy-pants coatings. They seem to last the longest, brand name and price notwithstanding.

http://www.usitc.gov/publications/701_731/pub4009.pdf

 

[tj0007]

Ok so I'll order the cheaper AC Delco rotors.. the picture on rock auto just looks like a normal rotor and all the dimensions are correct. Anybody ever paint the center part at home for the above mentioned "corrosion protection"? Or is that just a waste of time and rustoleum? Last set of new rotors I put on the front of the car were Wagner brand that Advance auto had in stock about a year ago and they had no paint or coating, and they still don't look rusted. None of the brands on rock auto mention galvanized.

 

[drewsdeville]

I recommend AGAINST the 'cheaper AC Delco" (Advantage?) rotors, or any other bare rotor. Last time I used them, they rusted from the inside out within a few years. I doubt you'll get a good enough rattle-can paint job on them to save them.

I highly recommend finding a set of galvanized rotors - unfortunately, you'll have to 'upgrade' to the try-hard slotted/drilled rotors. Powerstops are usually galvanized. They'll probably be the last set of rotors the car gets (depending on how you drive, that is).

 

[tj0007]

I recommend AGAINST the 'cheaper AC Delco" (Advantage?) rotors, or any other bare rotor. Last time I used them, they rusted from the inside out within a few years. I doubt you'll get a good enough rattle-can paint job on them to save them.

I highly recommend finding a set of galvanized rotors - unfortunately, you'll have to 'upgrade' to the try-hard slotted/drilled rotors. Powerstops are usually galvanized. They'll probably be the last set of rotors the car gets (depending on how you drive, that is).

Any idea where I can see pricing on Powerstops? Or any other galvanized rotors? Oh, and I just drive the car around town 1-2 days a week, and do a local car cruise that is 50 miles round trip once a month that is half highway half city. I'm guessing the fastest I would ever be going and have to slam on the brakes in an emergency would be 70-75mph like on i95 or the florida turnpike.. but that is rare. I've only had to slam on the pedal to where the antilock brakes engage 3-4 times in the last 7 years I've had the car and it stopped pretty good.

 

[drewsdeville]

I'm pretty sure they are on Rockauto's site. Take a look. Probably significantly more expensive than the others you were looking at. Other brands produce them as well. Just shop around.

I think the last set I purchased was "brakemotive" brand. They look a little goofy being slotted and drilled, but perform and look absolutely NEW, even after a few winter seasons.

 

[tj0007]

I'm pretty sure they are on Rockauto's site. Take a look. Probably significantly more expensive than the others you were looking at. Other brands produce them as well. Just shop around.

I think the last set I purchased was "brakemotive" brand. They look a little goofy being slotted and drilled, but perform and look absolutely NEW, even after a few winter seasons.

Awesome, Thanks to all you guys on here!

p.s. I just uploaded a few pictures of the car in the sticky "pics of you car" thread. I think they are on my profile page also. Whenever I get rotors I'll take some more pictures of it all on the car.

 

[MoistCabbage]

FWIW, because of the reduced surface area, slotted/drilled rotors will provide LESS braking power than solid rotors. If you're going to go that route, pair them with performance pads.

 

[dchavezo]

yeah, and those slotted and drilled rotors only show performance benefits in racing applications when youre doing repeated intense stops from 150-100 and need increased cooling capability. for normal driving applications standard pads and rotors should be absolutely functional and acceptable

 

[Slipgate]

If you didn't have vibration or a noticeable shake in the wheel, your old rotors are probably fine.

 

[Ranger]

Rotors get hot. Any paint you put on them will likely burn off as I suspect will the factory applied paint. I don't know what to say about galvanized or zinc coated. :noidea:

 

[BlueAngel#07]

I put some SP PERFORMANCE drilled and slotted zinc coated on mine. They cost a little but are what I feel to be worth it. They're cold drilled and dipped in zinc. View attachment 285881

And they have a lifetime warranty against cracking and won't rust. At least not yet

 

[MoistCabbage]

Some of the painted rotor paints/coatings are crap and are peeling and gone in months. Others last quite a long time. Zinc coated ones are better than painted, but harder to come by, and usually more expensive.

 

[mavric240]

Not all rotors are created equally. With brake's you get what you pay for!

Brake rotors are not offered in quite as many grades as brake pads are, but there can be quite a few. Rotor types include a basic economy rotor, a premium rotor, a drilled or cross-drilled rotor, slotted unit and a top-of-the-line rotor that is both cross-drilled and slotted. Basic rotors are usually manufactured from recycled steel and they meet the OE specifications for rotor thickness diameter and run out, but not much else is the same as an OE rotor. With the cheaper grade cooled rotors with fins between the two brake surfaces, you will notice the fins are much thicker and less plentiful than your original unit. Thicker fins allows the manufacturer to produce a less expensive rotor because the surface that does all the stopping, the machined surfaces, can be made thinner but the replacement will still have the same discard thickness as the OE rotor even though the life expectancy can be severely shortened. Thicker fins also mean less cooling is vented through the rotor causing the rotor to heat up more quickly and remain hot longer. This can effect the life expectancy of the calipers and pads as well as the life of the rotor and this is why the basic rotors are not recommended with a premium quality disc pad. The economy rotor will actually shorten the life of your pads because of this excess heat and could lead to cracked pads or glazed pads that are less effective in foul weather. For this reason, basic rotors are usually only recommended for use with the DIY or garage grade brake pads that are semi-metallic or fully organic, or with the economy-grade ceramic offerings.

Premium OE-specification rotors are made from premium quality new steel to exacting tolerances. They maintain the proper original spacing between both surfaces to ensure proper cooling and easy installation. Many are offered with an electro-plated hub to prevent rust and all rotors are machine-balanced for trueness. Premium rotors also have a thick braking surface that can often be machined on a lathe and re-used. This fact helps to further justify the added expense of using a premium rotor over an economy unit.

Many OE cars have performance application rotors from the factory which are drilled or cross-drilled to aid in dispersal of heat throughout the braking surface and in the case of the rotors that have cross-drilled holes; these holes are chamfered on the ends to reduce the chances of the brake pads cracking when sliding across the drilled openings. Rotors that are both cross-drilled and slotted offer the best cooling and dust dispersal of all the types of rotors available. So replacing these with cheap economy rotors will alter the braking of the vehicle and lessen the overall life of the braking system.

Matting the correct braking material to the correct rotor is important and will affect your braking if the wrong materials are used. "give me the cheap stuff" may be fine for a worn out car but lets say you have a 2010 CTS V or 2013 Impala then you should use what the OE engineered for it if that is an option you can afford

http://www.aa1car.com/library/brake_rotors.htm

 

[tj0007]

SO.. do you think I'd be OK with the "premium" listing AC Delco rotors? They're only $10 more a piece than the "economy" listing AC Delco rotors.. Both of them look almost identical according to the pictures on Rockauto.com, but different part number. Once again, the car is not raced or anything like that of course. A 50 mile highway cruise once a month is the upper extent of it's life. It is a very nice car(to me) and I don't wanna cheap out and put some no name rotor on to save $20 over all. Being in Florida, there's some rust but nowhere near what cars look like up north where roads are snow/salted.

And by the way, the stock rear rotors on the car are solid(no space/venting inbetween) and every single rear rotor shown on Rockauto.com is that solid piece without space/venting in the middle no matter what the brand. Some brands show holes and slots, but none are vented in middle.

 

[Submariner409]

Rear rotors handle only 30% - 40% of the braking load and are usually not vented.

Here's a set of EBC slotted "high performance" rotors - solid rear rotors. Zinc plated. Braking surface gets polished to chrome-like finish during breakin. Rest of the rotor area is still black after 4 years of snow/ice.

Surf through www.placeforbrakes.com and see if anything there floats your boat - and they offer free shipping - that means a lot for 60 pounds of cast iron.

"Basic rotors" are NOT made from "recycled steel". OEM rotors are machined gray cast iron. Machined steel warps under heat/cool conditions. Cast iron does not warp due to its random crystalline structure. (How come most brake rotor blanks are cast in China??? Because our iron smelting and casting businesses priced themselves out of the U.S. labor market. The Rust Belt) mavric240 needs to read his own supplied link.

EVERY rotor made for EVERY braking system has a minimum service thickness - if the rotor is worn or grooved to such extent that skimming will not exceed minimum thickness then it can be machined and reused. If machining exceeds the minimum thickness allowed, the rotor is junk.

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

www.ebcbrakes.com