coated rotors

[RT-NY]

Is there any disadvantage to getting coated rotors (actually, the entire rotor/hub assembly in my Dodge RT) over non-coated? Do the coating negatively effect heat dissipation? Does the coating actually last long enough to inhibit rusting? Is there any difference between black and silver coating?

 

[booster]

Is there any disadvantage to getting coated rotors (actually, the entire rotor/hub assembly in my Dodge RT) over non-coated? Do the coating negatively effect heat dissipation? Does the coating actually last long enough to inhibit rusting? Is there any difference between black and silver coating?

It all depends on the manufacturer's coating system, from what I have seen. Some merely paint them black or Silver, some are using some kind of plating, maybe and others may be doing a vacuum or powder coat and heat cure. The Hawk rotors we got over 10 years ago on the Chevy Roadtrek are coated and still very clean, but no salt or outdoor storing. The wife's CRV got Centrics a few years ago with their 700 hour salt spray tested coating and were rusting in 6 months. You don't want much if any coating on the braking surface, unless it is not the kinds that wear off and foul the pads. You are also much better off with high end light truck, police, ambulance semi metallic pads and not ceramic.

Rust will likely mess up heat transfer worse than coatings. I have seen all the cooling fins clogged solid and number of times from rust.

Be sure to always follow the pad break in procedure to get a good transfer layer of pad material on the rotors. They will look a gun metal color and very uniform if done correctly.

 

[RT-NY]

You don't want much if any coating on the braking surface, unless it is not the kinds that wear off and foul the pads.

Thanks, booster! From what I see, all the ones that I am looking at (cheap e-bay parts) do have coating on the surface that is supposed to wear off with break-in. Is the chance of fouling the pads enough of a reason to choose a non-coated rotor?

I have been using the Wagner Sever Duty semi-metallic, which have been working well.

 

[booster]

Cheap ebay rotors are often worth what you pay for.

If you don't have the capability to check the runout, you probably want to find someone who does to help you out as cheap rotors very often are out spec and need turning. I think you also have press in bearing races on your van so whatch those fits carefully as they too are often incorrect. That effectively adds enough to the price of them that they aren't cheap anymore. Buying local on rotors or someplace with free returns is a good idea, especially for the low end rotors.

 

[RT-NY]

But I do wonder if the local parts store is going to be any better in that regard -- I would guess their parts would be similar. Are there brands of rotors/hubs that would be considered more reliable or better quality for a 25 year old van?

 

[booster]

But I do wonder if the local parts store is going to be any better in that regard -- I would guess their parts would be similar. Are there brands of rotors/hubs that would be considered more reliable or better quality for a 25 year old van?

There are better brands, usually the major brands, maybe NAPA. Good rotors for big vehicles can be well over $100 each. Shopping local may not get you better parts on the low end stuff, but if they are bad (you need to check) you can just take them back without the hassles and shipping chargers and that is the big benefit.

 

[RT-NY]

There are better brands, usually the major brands, maybe NAPA. Good rotors for big vehicles can be well over $100 each. Shopping local may not get you better parts on the low end stuff, but if they are bad (you need to check) you can just take them back without the hassles and shipping chargers and that is the big benefit.

OK - Thanks for the advice! I see I can get Raybestos hubs at a reasonable price. They offer an "R-line" which is for regular use and an "Ultra-Premium" line that they say is
"designed solely for the truck market" -- based on what you say, I am inclined to get the latter. What do you think?

 

[booster]

Companies are often fogging the line between normal use and premium, but it you take a look at them if probably will be visible if they are different. Country of origin also can matter and it should be called out on the packaging. I assume you are talking about the bearing hubs and probably have separate rotors?

An interesting and unexplainable to me thing is going on with Rockauto. Their "economy" listings in their product listing are now mostly more expensive than their "daily driver" listings and often as high as the "premium" listings. It is a recent thing, I think.

 

[RT-NY]

Companies are often fogging the line between normal use and premium, but it you take a look at them if probably will be visible if they are different. Country of origin also can matter and it should be called out on the packaging. I assume you are talking about the bearing hubs and probably have separate rotors?

The Dodge Ram Vans have a single rotor/hub assembly. These are made in china, though I would think that most parts for my van are, no? I do wonder if the fact that it is a brand name makes any difference at all. But perhaps Raybestos imposes some kind of quality control standard.

 

[booster]

The Dodge Ram Vans have a single rotor/hub assembly. These are made in china, though I would think that most parts for my van are, no? I do wonder if the fact that it is a brand name makes any difference at all. But perhaps Raybestos imposes some kind of quality control standard.

The good companies do/did put their own quality standards in place in China. I know because I did just that at one job I had. The biggest issues is finding non buyable quality inspectors in some offshore places. Many have gotten bought off and passed substandard stuff. Bendix and Raybestos are old line companies and our vans are some of the small stuff they sell compared to the over the road stuff. I think liability alone would make them pretty careful.

Historically, there probably was a different alloy used in the castings for the premium stuff and many places still claim they do that. With a metallurgist to check it out you never know unless it fails. Cast iron need to be poured correctly into well designed molds and carefully cooled to give good properties. Sometimes it is aged by time or artificial means also, so can have quite a variations. If you see voids, hard spots, or grain lines in the machined areas you need to beware and perhaps check other ones.

 

[Pilgrim-ClassB]

For aftermarket parts I trust NAPA more than other sources. Raybestos is a long-established brand that I have used with good results. Bendix is also a good brand.

No coating will last on the contact surface of brake rotors will last - the pads clamp down and their function depends on having good contact. No coating I know of stands up to that. Personally, I am not aware of any benefit of having "coated" rotors. It's not something I would pay extra for.

A thin bit of surface rust often appears on the surface of brake rotors within days of being parked or not used, especially in humid atmospheres. This is normal and scrubs off the first time the brakes are applied.

Keep in mind that brakes are a critical safety assembly. Don't go cheap on them.

 

[Mtsailor]

I went with NAPA for the rotor/hubs for my Dodge Roadtrek thinking I would be more likely to be getting good quality. One of them was slightly beyond the maximum spec for runout. On the replacement, the bore for the wheel seal was machined too large such that the new seal just dropped in. I guess you need to check carefully regardless of the source. At least with NAPA the return/replacement was quick and easy.

 

[RT-NY]

No coating will last on the contact surface of brake rotors will last - the pads clamp down and their function depends on having good contact. No coating I know of stands up to that. Personally, I am not aware of any benefit of having "coated" rotors. It's not something I would pay extra for.

The coating, as I understand it, is supposed to slow the rusting around the cooling fins, and also along the edge of the rotor where the pads don't reach -- I heard someone suggest that when it starts to rust along the edges, the rust can creep down along the surface of the rotor.

IOne of them was slightly beyond the maximum spec for runout. On the replacement, the bore for the wheel seal was machined too large such that the new seal just dropped in.

That is awful! If the seal just dropped in, then I guess the race would have as well. I am surprised that a part like that would make it through quality control at all.

 

[Mtsailor]

The seal was a larger diameter than the race. The bore for the race was correct.

 

[Sensfan-ClassB]

This thread is very informative. I have been following brake related discussions, as the braking system on our 2012 Chevy Express 3500 190-Ranger is original. After 160,000 kilometres and 13 winters parked outside, my garage tells me that the braking system is still in good operating condition; rear pads are currently measuring 8 millimeters.
While operating on highways I use the cruise control and manual gear shift settings interactively, especially during climbs and descents, to optimize fuel efficiency and engine braking.
Go Oilers!