('04 Cavalier) I need to replace the disk rotors. Everyone hereabouts
seems to have two varieties: one at $22-ish, the other at $38. The $38
ones have a longer warranty, but only for "defects".
My guess is, the $38 ones are 'better' (more metal?); but, it could be
just charging more for a pretty meaningless warranty. Does anyone know?
I've seen the same, and I dont know the real answer, BUT if you compare
this with brake pads price and quality, you will definitely see a quality
difference with the more expensive pads.
And I would not put cheap rotors on my car, regardless.
Out of some sense of statistics, why did you find it necessary to replace
Well, they're warped ... thump, thump, thump when I brake. As to why,
and not to be blaming any one particular person, but it seems to have
started after someone I'm married to went down a long hill. Which has
happened in the past, depending on who's doing the remembering.
We bought the car used. Considering who we got it from, my guess is, if
there is such a thing as cheap aftermarket rotors, that's probably what
they had on there.
Take an old rotor to the store if possible.
Sometimes they put unexpected rotors on cars at the factory.
Had heavy duty rotors on my '88 Celebrity sedan.
The auto store book said they should only be on wagons.
Had to make a second trip.
Think the only ones they had were 18 bucks each.
Made in China, but they looked the same as the originals.
Didn't have them cut true, as some people recommend.
No problems with them.
Unless you're a metallurgist and can test them, just compare them as
best you can and pick what you think is best.
The counterman can put both in front of you.
Making sure the tires aren't over-torqued is one way to prevent
But I think some rotors will warp from overheating.
My Celebrity rotors were thumping, but they were also deeply grooved.
If they were warped that's probably what caused it.
Had about 150k miles on them.
I think overheating will warp them too, especially if the torqueing is not
On things I consider critical, including brakes and tires, I dont bet my
life on a couple of bucks. There are areas where one can go with the
cheapo parts maybe.
Warped rotors is a major cause of complaints nowadays. There is
some disagreement about exactly why this happens, but I think that
we would all agree that just using the brakes going down a long
hill should not cause this.
If this link still works, there is a good bit of useful information on
In addition, never let any jerkwagon tire changer use an impact wrench to
put your wheels on your car. Torque wrench all the way.
You should be able to tell by looking at them.
Have them get both kinds for you then check them when
they come in.
Some really cheap ones are thinner, don't have as many
cooling fins, etc.
Everything is made in China, but some are better than others.
I hear what you are saying, but when metallurgy is involved, I dont
believe you can tell by looking. Certain good machine work looks
better, usually, than crappy machine work. Metallurgy??? A
Good point. Hopefully good machining and more metal is
indicative of better metal. It would be a shame to
use poor metal with good machining.
There was an article on the subject in Pop. Mech. about a
year ago. I will see if I can locate it.
Go the the store and ask to see both rotors. Buy the one with more
metal. In my case, I'd probably get the cheap rotors. My old Cavalier
was a great car and served me well. For me, only the cheapest parts
would go into that baby. :-)
I read a startling article that said that the pulsating rotors are
actually caused by transference of pad material onto the surface of the
rotor at a molecular level which causes uneven braking. Beats the heck
out of me if this is true but if it is, then breaking-in the pads could
be critical. My understanding of the article is that applying the brakes
after heating them up will cause a visible imprint of the pad onto the
rotor. Weird stuff!
I dont believe that. When I have chocked up the rotors in the brake
lathe, there is definitely a significant warp. I have never seen much
pad material transfer to the rotor surface, but then again I buy good
There are several factors at work here.
"in more than 40 years of professional racing, including the Shelby/Ford
GT 40s – one of the most intense brake development program in history -
I have never seen a warped brake disc"
this is preceded by:
"presuming that the hub and wheel flange are flat and in good condition
and that the wheel bolts or hat mounting hardware is in good condition,
installed correctly and tightened uniformly and in the correct order to
the recommended torque specification"
you will find that in most cases, simply scraping surface rust off the
hub/wheel interface, applying a little antiseize, and correctly torquing
fasteners will cure most "warped" disks.
the fact that disk machining also "cures" is usually due to the
coincidence that cleaning is done at the same time.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.