Hey Scotty,
Some years back i had a 2005 Dodge Magnum R/T (Hemi), the first year of the Magnum and Chrysler 300, that I put 170,000 miles on doing sales work all over the place. For the first 100,000 miles I was having endless issues with my front brakes pulsating, after 3-5K miles after new or turned rotors the pulsation would always return. I finally decided to put drilled/slotted rotors on the front of the car, and that completely resolved the issue. I believe the reason for this is because (as i have come to understand) pulsating brake rotors don't "warp", but they overheat under normal use and then material from the brake pads fuses to the rotors when you come to a full stop (like at a stop light). The Magnum just didn't have properly sized brake rotors for the weight of the car. The drilled/slotted rotors dissipate heat faster and clear away material on the pad through the slots, and they worked like a charm.
A couple years ago I bought an 03 Honda Accord (that year had rotors in the fronts/drums in the back) as an around town beater and after a few thousand miles, the front brakes started pulsating. I told my mechanic i wanted to put drilled/slotted rotors in the front to resolve the issue, and he all but refused, stating that drilled/slotted rotors were fragile and broke and blah blah blah. I agree they might not last as long, and they may be more fragile but under normal driving isn't an issue, and my theory about the 03 accord (first year of 7th gen accord) was it didn't have enough brake surface area (they went to rear discs in 04 i believe) and that's why I wanted drilled/slotted in the front.
Anyway, I'm just an amateur/weekend mechanic but I got into quite a heated argument with my mechanic about the causes of brake pulsation and my explaining the benefits of drilled/slotted rotors over solid rotors, and they really don't cost any more. What do you think?
The mechanic is right. People buy those gimmicky rotors for the appearance. I think he has seen his share of cracked ones. Yes the slotted ones clear away pad material, which is really good for converting your pads (and hard earned money) into dust.
Warping is simply caused by crappy pads & rotors. You want as much meat on there as possible, and good metallurgy. It also has a lot to do with poor braking habits, like riding the brakes, and abrupt stop and go driving.
well i totally disagree with you, and i hope Scotty will chime in (though he may not take my side). Drilled and slotted rotors are not gimmicky, and my experience from the Dodge over several years and many miles will never change my mind about that. I also have a 2006 Porsche Cayman S with the original drilled/slotted rotors on it, and Porsche is not indulging gimmicks. Saying that brake pulsation is due to crappy rotors/pads is just not accurate. I have put factory rotors and upgraded to top-of-the-line solid rotors on cars and had the same issues. The solid rotors are horrible at heat dissipation, and in heavy vehicles are a nightmare. Car manufacturers are always looking to save a buck and frequently under size or use the wrong kind of rotors.
Improperly or unevenly torqued lug nuts will cause warping too.
Porsche doesn't have gimmicks? {pear}:laughingoutloud: That's a good one.
https://www.youtube.com/watch?v=0MhnbnBf0UY
i've never had an issue with my porsche in the now 8 years i've owned it. this has nothing to do with the original issue i raised, you are a troll. you have no idea how brake systems work.
Porsches are baubles you parade in your driveway or next to a city curb to impress people.
More mass requires more energy to heat up.
Here a is a Le Mans racing car, with big, thick, smooth rotors.
Scotty: "A lot of it has to do with YOUR DRIVING SKILLS"
https://www.youtube.com/watch?v=gx1KQ66NJUk
As far as I am concerned, Porsche became extremely "gimmickee" when in the late 70s they came out with that ridiculous CIS fuel injection and then the utter failure 928. They have been going downhill ever since.
I appreciate your comments but you're still not convincing me you have any idea what your talking about regarding the cause of brake rotor vibration (including scotty). One clue is that no one has mentioned the "bedding in" procedures that performance brake companies advise when purchasing their rotors and pads (and this applies to ALL rotors and pads, but hardly nobody does it). The bedding in procedure involves making a series of 60 to near zero stops to super heat the rotors to create a hardened/conditioned surface between the rotors and pads, making them more efficient and avoiding issues that causes rotors from "warping". rotors do not warp, brake pads get hot and fuse material onto the rotors, and over time, causes uneven surfaces on the rotors. the "bedding in" procedures that brake manufactures recommend are to prevent this from happening, but hardly anybody actually does it. getting the rotors hot does not cause warping by itself..its the material from the pads baking onto the rotor when the vehicle comes to a stop with the brakes still applied, like a stop sign or traffic light.
"bedding" instructions on new brakes are usually just to avoid severe stops for the first 500 miles.
"bedding in" is getting your rotors extremely hot to create a layer/properly burnishing a surface between the rotor and the pad. read about it
Well you seem to already know everything, so I guess you don't need us. Good luck.
Its more important than that, I would suggest googling it. As indicated in my original post I dealt with constant brake vibration in the Dodge for 100K miles before I finally researched and understood the causes of "warped" rotors, such as not following the bedding in process recommended for the rotor/pads. As an example of heat not causing rotor warping, I recently went on a trip with my MG and one of the front calipers got smoking hot over a long trip because of a bad rubber brake line not relieving the brake fluid pressure. I got that rotor so hot it was like there was a fire under the car (i was actually worried the car was going to catch on fire)...I fixed the brake line, caliper released, and the rotor isn't warped at all. Brake rotors don't warp because of heat, its a common misconception. They get "warped" because of the material baked onto them when they sit, after being overheated. This can also happen if the car sits and the rotors rust between the surface of the pad and the rotors, although that is usually easier to clean up with some good heavy braking.