Having spent many years as a line mechanic, I have turned or ground a great number of rotors. Many just to provide a fresh surface but many more to correct runout. Runout meaning that they were warped. And just so you know, they warp because of overheating. When they are new or freshly resurfaced, there is no pulsation (other than what is created by ABS.) Because there is no runout. Once they warp, which only takes one serious overheat, they will overheat much more easily because some areas overheat more quickly.

If you can't explain yourself, provide a good link and be prepared to defend it.

 

Who rotates your tires? 9 times out of 10, warped rotors are from the lugs being torqued down unevenly. Watch them next time, my guess is you'll see them run the lugs on with an air wrench, then click click click with a torque wrench (already past spec) and they're done. I rotate my own tires, but if I do have to go to a tire store for a leak, etc, I tell them to run the lugs on by hand and stand there and watch them.

 

My tire shop has windows to the garage area. Once I finish my 2nd or 3rd cup of complimentary coffee I help myself to the garage area and watch them all up close and personal like.

 

I had trouble with what I though was warped Rotors. The Ford Tech found that the Front hubs of my 2004 F-350 4x4 was leaking a very small amount of Diff. oil onto the rotors. Replaced the hubs, turned the Rotors and replaced Brake pads. That has been over a year ago. No Problems now.

I have heard that mounting wheels back on the truck that rotors can be warped if over tightened.

 

Why would you believe everything you read online? I have some money in Nigeria I want to get to the US and need your help.

I've read the BS like this on many sites. "Rotors do not warp, the pads actually cause a buildup on the rotor, which causes the pulsation when braking."

See StopTech : Balanced Brake Upgrades which says "...every case of "warped brake disc" that I have investigated, whether on a racing car or a street car, has turned out to be friction pad material transferred unevenly to the surface of the disc"

Like I said, it is all BS. Rotors that get hot and then then a section is exposed to cool temps (like driving through a puddle when your brakes are hot) causes the rotors to warp.

 

Don't even need the cool factor. Just repeated use, usually downhill, and the rotor gets heated beyond the range where the metal is stable. Continued hard braking distorts the disk. Happens every day.

 

Sorry, but have to agree with CunMud. I too read that StopTech article and then applied their principles to my driving. Never a warped rotor since.

 

While some of what is discussed on that stop tech website is good stuff, I disagree with the "rotors don't warp" statement. It doesn't take much of a distortion to feel like a severely warped rotor. The 99-04 trucks are more susceptible to over heating the brakes, my 05 has never had an issue with warped rotors, and it gets ridden hard and put away wet, pushes too big of a plow, and hauls way more weight than it should; but hey, that's why I own fords! We tried slotted rotors on one of the 2001's, but they rusted out prematurely. Most of our trucks have more problems with rusty rotors due to sitting than anything. Rust on the rotors can make it feel like the front end is going to fall off when hitting the brakes.

 

With regards to rotors, I have previously run Brembo OEM replacement rotors that are cryogenically treated at Diversified Cryogenics, making them almost as hard as stainless steel- Applied Rotor Technology in California provides the same product. Unfortunately, Brembo, Powerslot, Raybestos, Bendix, Hawk etc. are all purchasing their rotors from the same foundary in China (with the exception of the $300 each composite high end units for Ferrari, Porsche, etc). Both companies purchase the highest grade rotors made, laser mic them for quality, scrap the ones that are out of spec and cryogenically treat the good ones which are now as strong as stainless. They will also slot and cross drill the rotors for you. Their service, price and quality are excellent as well.

For street use, slotted/drilled rotors are just “cheese-graters” for the brake pads IMHO, because unless you are involved in true racing conditions, the brake linings do not produce the gases which slotted/drilled rotors are designed to relive. In some cases, brake testing indicated reduce brake efficiency in street-based operations using slotted/drilled rotors when equal comparisons were made. The staff can speak to you as well regarding those options, but I am very satisfied with the performance & wear of these products.

 

If your drilled or slotted rotor are "like cheese graters" on you pads they are just plain badly done.

The drilling and slotting actually reduces the swept area and allows more air to circulate, helping to cool the disks. The reduced swept area has the effect of increasing the psi of pressure applied to the disk.

For your info, stainless comes in various hardnesses, so saying "as hard as stainless" is no measurememt at all.

Most stock rotors/disks are just cast iron and they serve the purpose very well. In heavier vehicles they need to be vented to increase the cooling ability.

Just ducting air so that it is directed onto the disk and caliper makes a major difference in cooling the brakes. (Use air from in front of the vehicle.)

 

02 original pad and rotors... No warping. I don't check my lug nut torque. Unless I use German torque specs. (goodNtight). Been waiting for the day when I look at the pads and say wow it finally time to change you little devils.

 

Not a lot of mountain driving in New Bern, right?

 

You don't use a torque wrench, or you don't double check the tire shop's tightening job? If you do your own, without a torque wrench, that's just asking for trouble.

 

1. Unless you are functioning at a level that produces gases (such as racing conditions), slotted/drilled rotors serve no purpose in street applications- numerous test by both the oem's & independent group have verified this. If you contact ART or DC they can discuss the details & provide copoes of said reports.

2. While many of the detroit oem's are still cast iron, many vehicles were equipped with rotors of cast aluminalloys (or lightweight junk)

3. Venting by itself for heavier vehicles is initself a misnomer.....since if this was an effective solution it would be used by the oem's as standard equipment in medium and heavy trucks (such as trash vehicles, fire engines, ambulance chassis, etc.)- they are not nor do the oem's recommend their use in these applications.

In both HD truck and racing applications, cryogenic treatment of rotors & drums have been in use for over 30 years (and yes, there are still a few oval track racing classes that even require drum brakes) and their effectiveness in these applications is "common knowledge" and readily available.

While you are correct that there are variyng degrees of hardness of any metal (including stainless steel) which most peopl are not familiar with, I use the reference to equate the gain that will occur- if you have cast-al rotors, they will now perform as if they were cast iron; if you have cast iron, there hardness and resistance to change from heat as a result of their ability to dissipate heat more rapidly will improve by the same margin.

Considering the cost of cryo tx is typically $10-15 per rotor/drum, it is a very inexpensive and effective purchase for most street vehicles.

 

Wow, we have gone a little off track here. Your first point is wrong as proven by thousands of disk brake users who have suffered from chronic warpage. They change over to drilled/slotted rotors and the problem ends. This is due to the increased ability to quickly dissapate heat. People who live in mountainous areas that carry heavy loads KNOW this.

On your second point, we are talking about Ford trucks here. Not some "economy" car and certainly not race cars. And your characterization "many of the detroit oem's are still cast iron" seems to imply that iron disks are going away is just wrong. Unless some miracle material that is cheaper than cast iron is developed, cast iron will still be the choice of all but the most exotic manufacturers.

On your third point you say "Venting by itself for heavier vehicles is initself a misnomer" I can only guess that your experience is limited to what you read on the internet or car magazines. Vented disks, assuming you know what they are have been around since the sixties and are very common because they are more effective at dissapating heat. And as to your assertion that ANY oem does not recommend their use in ANY application sounds like something you just pulled out of the air. The only reasons that vented disks are not used in more applications is that they do slightly increase unsprung weight and they cost a little more than plain disks.