Why do the rotors warp? - Page 2

zzyzzx · 05-17-2010, 09:36 AM

Quote:

Originally Posted by AndysGX

Did we ever figure this out? Is the car too heavy, or the lug nut torque specs too high....?

According to my 1999 Owner's Manual, it's 100ft lb torque. That's what I set them to yesterday. Now that I have had more time to think about it, that's clearly way too high! For every other car I've done, it's usually 65-75 ft-lb, and on only 4 lugs. I can't imagine why a car with 5 lugs would need a higher value.

I haven't checked my factory service manual to see if it gives a different number.

zzyzzx · 05-17-2010, 09:37 AM

Quote:

Originally Posted by cherrington17

considering the pic... i apparently always buy chinese rotors. Even the Bendix rotors i got, were the same as the one on the left.

So where do I find the ones on the right?

All part of our race to the bottom! My OEM rotors do look more like the ones on the left too, but it's impossible to say unless you can compare the two (since it's a relative thing). I'd want to look at ones from NAPA and CarQuest.

Cliff8928 · 05-17-2010, 12:31 PM

Quote:

Originally Posted by lord2heart

is number 6 true on our cars?

Pretty much, Even with my big 2 piston calipers I never have to add brake fluid throughout the life of the pads. But only the fronts wearing down isn't really enough to turn on the light.

Quote:

Originally Posted by zzyzzx

According to my 1999 Owner's Manual, it's 100ft lb torque. That's what I set them to yesterday. Now that I have had more time to think about it, that's clearly way too high! For every other car I've done, it's usually 65-75 ft-lb, and on only 4 lugs. I can't imagine why a car with 5 lugs would need a higher value.

I haven't checked my factory service manual to see if it gives a different number.

Factory specs for lug nut torque on most GM cars is 100 FT-LB for 12mm and 140 FT-LB for 14mm.

Nate's Alero · 05-17-2010, 02:01 PM

when mine wear out. i get like a year out of my brakes. i wish my rotors would STOP doing this. when i did the brakejob on zoL's alero. those R1 rotors were like... AMAZING. if anyone wants to get a good set. get those.

lord2heart · 05-17-2010, 02:28 PM

Quote:

Originally Posted by Cliff8928

Pretty much, Even with my big 2 piston calipers I never have to add brake fluid throughout the life of the pads. But only the fronts wearing down isn't really enough to turn on the light.

awesome! just learned somthing new!

do you know what light comes on in the cluster?

zzyzzx · 05-17-2010, 02:30 PM

Quote:

Originally Posted by Cliff8928

Factory specs for lug nut torque on most GM cars is 100 FT-LB for 12mm and 140 FT-LB for 14mm.

Wow! Anyway, do you guys also keep a breaker bar in your car? I doubt that I could get the lug nuts off, even with my lug wrench that I keep in the car (not the one that comes with the car).

For my GF's Subaru it's speed at 65ft lb and my Escort I think 75.

Cliff8928 · 05-18-2010, 02:29 AM

Quote:

Originally Posted by lord2heart

awesome! just learned somthing new!

do you know what light comes on in the cluster?

The "BRAKE" light... Same as the parking brake.

Quote:

Originally Posted by zzyzzx

Wow! Anyway, do you guys also keep a breaker bar in your car? I doubt that I could get the lug nuts off, even with my lug wrench that I keep in the car (not the one that comes with the car).

I have no issues at all getting 100 ft-lb lugs off the car... It's nothing for the average person to be able to put a little over 100 lbs of pressure on a lug wrench. And most are over 1ft long.

Monza · 05-18-2010, 11:00 AM

Any time a tire shop mounts my tires I loosen and re-torque all the nuts correctly. Some times they're pretty good. Other times they're tighter than a bear's ass. No way I'd get them off by the side of the road. And it may cut down on warping wheels and rotors.

AndysGX · 05-31-2010, 05:01 PM

So I tried the garnet paper suggested in the link Cliff posted. It works great so far. Mine were getting bad, even a grinding noise, but now they're silent & no vibration at all.
I used 150 grit paper on a block, and hit each rotor for about 20 minutes. Then brake cleaner. Total cost: $7.

TheThickster · 06-01-2010, 05:04 PM

I read an article that said rotors dont warp and all this talk about rotor warping came from auto racing. The article explained that its in the manufacturing process, cheap rotors are not cast or machined well, and the good expensive ones are. IIRC it was the Counterman Magazine

undersc0re · 07-25-2010, 09:41 AM

I just had an issue with warped rotors replaced 2 front lefts within 2000km. The original job was new pads and rotors stock. Only noticed the shake with firm braking from approx 75 km/hr. Would these be so cheap that maybe the mating surface from the rotor to the wheel or from the rotor to the hub is defective? I do not brake hard, and the new rotors gave me the shaking problem only with a firm braking from higher speed. I feel it a little with lighter braking from high speed as well. Is there a way for us average guys to check the rotor mating surface for bad specs before application....or is that a little too technical?

cherrington17 · 07-25-2010, 12:13 PM

i have a huge issue with the outside and center of the rotor rusting. total PITA..

...and makes it even more of a bitch to get the caliper off for a brake change.

robalero · 07-25-2010, 12:41 PM

thats something you can fix, before installing of new rotors paint the center with rust-proofing primer or black rust proof stuff and it will prevent most of the rust apperring, however the top part of the rotors will still have that unless you buy really really high end rotors

widbyj · 07-25-2010, 02:10 PM

^^^ forgot step two

1 - Tape off the area where the pads will rub (doesn't have to be real accurate)
2 - Using Brake Caliper spray paint do the centers (both sides) and all around the edges (get some inside the vents also)
3 - remove tape and install when the paint is fully cured

Note: The cheaper the rotor the faster it will warp. ABS, if/when it kicks in, will warp rotors at higher speeds. Drilled/slotted can help reduce rotor heat and warping.

robalero · 07-25-2010, 02:53 PM

drilled/slotted also look cool lol, but they do help you stop better in the rain I find when I use to own it on my other car

undersc0re · 02-12-2011, 11:29 AM

Siezing caliper or calipers will cause warping to your rotors, the caliper may not be full on siezing but just enough to heat up and warp those nice new rotors you just put on. You should notice when you push the piston back up into the caliper if its really hard to do. I had a caliper sieze at approx 150,000km on my 2001. I only noticed after going to the car wash and when I sprayed the one wheel it made a huge steam bath in the car wash! Where as the other wheel was fine. Explained my rotor warping after only 2000 kms. Not sure if its possible but if its warped enough it may even throw off the wheel bearing sensor!?? and give you the 3 wonderful dash lights?! not positive on this but seems possible.

scott192 · 02-12-2011, 01:03 PM

i got the slotted ones ands there great so far

Cliff8928 · 02-12-2011, 01:24 PM

I'm nearing up on 53k miles on my 12" rotors from the original install way back when with no issues at all...

The only reason I'm going to replace them is to upgrade to 13" (or rather 12.98")

doubleN0alero · 02-12-2011, 01:30 PM

Quote:

Originally Posted by [ion] C2

Seriously? You think a chain store would carry drilled or slotted rotors?

Aleromod Upgrades > Performance > Brakes > Rotors

I got Baer a few years back from either advanced or autozone and they were still going strong when I traded in 60K miles later. I want to say they were 250 or 300.