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Old 06-09-2003, 02:29 PM   #1
BoardRider
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Question Help: My brake rotors are warped

I bought the car back in December and the rotors were slightly warped then, but it's has been bad enough recntly that I think it's time to replace 'em. I don't know much about brake rotors, so I could use some advice.

Since I'm doing it, should I replace all 4 at the same time, or should I just do the front 2?

I don't need (or want to buy) any high performance, high price rotors. I commute 36 miles for work each day and I like to drive pretty aggressively around town, but I don't autocross or anything like that.

Can anyone point me in the direction of some decent rotors to replace the existing ones?

Thanks!
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Old 06-09-2003, 06:10 PM   #2
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Are you sure you need to replace them? Most often enough material remains that you can have them "turned" to remove the ridges/pad material.

Otherwise Id replace the fronts first.
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Old 06-09-2003, 06:55 PM   #3
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Yea... check with the shop if they have enough thickness left to resurfarce them.. baicly they will grind off the rough spots to make em round again.. if not.. then it's time to get new ones.. also I would recomend going with non-metailc pads as well when you replace them. They are much gentle on rotors and are good for street driving.. EBC makes good ones.. you can get rotors and pads at www.tirerack.com. Maybe even local retailer will care them..
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Old 06-10-2003, 07:07 AM   #4
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BoardRider,

If you are genuinely hard on your brakes (and ride them when stopped for example) stay away from EBC greens IMHO. They have been the source of more headaches than you wanna know about for "spirited" drivers due to them dropping material/resin onto hot discs (giving the impression of warping). If you don't wanna take my word for it, go ask someone like Steve Gavin at DBA, too...

<flame suit on>

HTH - or at least prevents the pain of finding out the hard way (and yes, quite a few people have had acceptable resulots from them, but mnay have not).

Cheers
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Old 06-10-2003, 08:50 AM   #5
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I'll second the suggestion to stay away from EBC. They are a "relatively" cheap alternative for pads. They provide decent performance at the cost of rotor wear and shudder issues.
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Old 06-10-2003, 01:58 PM   #6
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anotherb4,
What do you mean by "ride them when stopped"?

Thanks for the input everyone. I will take my rotors in to get turned. Hopefully they have enough material left. If not, I will be back to get advice on which rotors to get.
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Old 06-10-2003, 03:45 PM   #7
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I generally replace rotors instead of having them turned. I don't like the idea of removing rotor material and have found turned rotors warp pretty quickly.
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Old 06-10-2003, 05:00 PM   #8
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Angry Legacy brakes/overweight

My Legacy 03 GT is grossly overweight at 3600. The brake rotors warp down any mountain pass, the clutch stinks on any hill start, and I doubt the engine will long outlast the warranty. Is there an official fix at least on the brakes? And any admission that the overweight design puts all owners behind the eightball?
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Old 06-10-2003, 06:53 PM   #9
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Quote:
Originally posted by BoardRider

What do you mean by "ride them when stopped"?
After using the brakes heavily and the rotors/ pads become quite hot, you do not want to sit at a light/stop sign with the pads clamped to the rotor (foot on the brakes).

This can have two unhappy results:

1. the rotor which has been evenly heated during the stopping now has a large area which will continue to radiate heat out to the atmosphere and a smaller area (where the pads are clamped) that will remain quite hot. This differential cooling can cause deformation (warping) of the rotor if it is severe enough.

2. The very hot pads clamped against a stationary but equally hot rotor encourages the transfer of pad material to the rotor where it is baked on. The resulting clump of material is often mistaken for a "warped" rotor due to the resulting pulsing feeling when the brakes are subsequently applied.

Good luck.
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Old 06-10-2003, 08:51 PM   #10
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klockridge - you should be grateful that in MY02 the Legacy GT's recieved the 11.6" rotor up front. The MY00-01's still had the smaller 10.9" rotors up front.
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Old 06-10-2003, 09:13 PM   #11
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Thumbs up Thank you, mch!

Bang on - and some pads have more of a tendency to do this than others...some discs are better at dealing with the heat, too.

Quote:
Originally posted by mch


After using the brakes heavily and the rotors/ pads become quite hot, you do not want to sit at a light/stop sign with the pads clamped to the rotor (foot on the brakes).

This can have two unhappy results:

1. the rotor which has been evenly heated during the stopping now has a large area which will continue to radiate heat out to the atmosphere and a smaller area (where the pads are clamped) that will remain quite hot. This differential cooling can cause deformation (warping) of the rotor if it is severe enough.

2. The very hot pads clamped against a stationary but equally hot rotor encourages the transfer of pad material to the rotor where it is baked on. The resulting clump of material is often mistaken for a "warped" rotor due to the resulting pulsing feeling when the brakes are subsequently applied.

Good luck.
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Old 06-10-2003, 09:48 PM   #12
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Couple of quick thoughts:

1) Pull your rotors and have them checked for thickness (how much material is left on the rotor itself) and run-out (how much iwobble it has, in and out, across each rotor "face" (front and back portion of each rotor where the pads clamp). If you have the tools, a brake micrometer and a dial indicator, you can check this yourself. If not, a good brake shop can do it for you.

2) If you've got good thickness and some run-out, you may be able to machine/dress the surface and take out the run-out. This is where wisdom should prevail because you don't want to machine out all of the run-out and leave yourself at absolute minimum thickness (which is indicated on the inside surface of the rotor). If this is the case, then you're looking at a very short timeframe before your braking action is compromised. In this scenario 1 of 2 things will happen; 1) you'll rapidly overheat the brakes and cause major warpage or 2) you'll cause the rotor to overheat and crack, both of which are not good, trust me

3) If you've got limited thickness, then I'd just replace the rotor or rotors depending on what the conditions are for each corner of the car. Sometimes you'll need to replace both the front and the back, moreoften just the front and usually, just one side because the opposite rotor can be machined/dressed to bring it back into spect.

I've got to run out but could someone talk about break in (seating) procedures for the brake pads/rotors? Thanks.

Let us know how things come out.

Br, Dale
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Old 06-11-2003, 08:58 PM   #13
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Many thanks, mch and others. The rotors deformed a bit and caused wheel shake midway down a pass that I've descended easily in four other cars. Problem got better once the brakes cooled in the flats ( I made it down on engine braking and no traffic). Dealer found rotors off true and ground them . I submit: ANY car should be able to descend a mountain pass, and the long multilogues among Legacy owners posted on this site concerning wheel shake and rotors tells me what I know from years as a consultant in the industry: the Legacy is overweight with inadequate brakes and probably other systems. The answer is to register complaints with the National Highway Safety complaint system, so Subaru notices and dealers stop taking heat for bad product planning. Better ventilation to the front brakes is one fix. Try to fix it yourself with aftermarket parts and there goes the warranty. I like these cars but a lemon year is a lemon year?I've never had a new car I had to baby and rebuild! KAL
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Old 06-11-2003, 09:58 PM   #14
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I dont agree that the brakes arent designed correctly. Sure they have less leeway but I feel its your/his driving style causing the problem.
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Old 06-11-2003, 11:02 PM   #15
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cipher, Thanks for the reply, but I routinely drive other cars down that pass in the same normal fashion without problems. The idea that I have to baby my Legacy-stop to cool the brakes-makes my point. New annual models frequently come in overweight if higher ups don't ride herd, with such consequences. It was a management problem at Subaru, is my best guess. The chat on this site seems to me to confirm it. To live in the mountains is to understand how great an art it is to design a car for all conditions. The five other vehicles iu've taken down this national highway do fine, but, alas, not my new Legacy.
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Old 06-12-2003, 12:34 AM   #16
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As far as I can tell, a Legacy GT is 3363lbs for a manual transmission sedan. Are you sure you have a Legacy? The heaviest Legacy is the 2.5 GT automatic wagon at 3535 lbs - closer to 3600, but not quite there.

As far as braking goes, it should indeed be more than adequete. I don't know what other 5 vehicles you own(ed) are, but if they were all Porsche's then the braking may not quite match up to your expectations. OTOH, you may simply find yourself driving the Legacy harder/faster than your other cars down the mountains - I know I do.

Cheers,

Paul Hansen
www.apexjapan.com
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Old 06-12-2003, 05:47 PM   #17
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Shirokuma, Good points. So let's say 3500. Other cars included a 91 Mazda 626 which outperforms the 03 Legacy easily, a rented base Impreza fun to take down the pass with all wheel drive, ..pretty standard cars yet fun each in its way. I thought I took the Legacy down in similar moderate-plus fashion. Why all the chat about Legacy rotors and wheel shake if there is no problem? Let me try it again more moderately still. Will get back to you all. Many thanks. KL
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Old 09-08-2003, 03:11 PM   #18
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I know it has been a while but I still haven't made it to the shop to get my brakes checked. Busy!!! But I did call them last Friday and the guy told me that he wouldn't turn the rotors on my car because of the way that the Subaru rotors (for my car?) are produced (material, heat treated, etc.). He said because of that, he won't turn them and that I would have to buy new ones.

Has anyone ever heard of this?

Also, what is the minimum rotor thickness (97 GT)?

Thanks!
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Old 09-08-2003, 04:05 PM   #19
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Could my rotors be warped? I have been having SEVERE shaking when stopping under light to moderat pressure, yet under heavy braking, not much shaking at all. I don't feel the pedal pulsing, but that may just be my imagination. My dad and I checked the rotors with a pair of dial indicators shortly after this started, but found the rotors to be in good shape. I may try getting them turned to see if that may be the problem.
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Old 09-08-2003, 04:15 PM   #20
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Well, if it's just pad material, you can try and 'clean' them first. Get them good and hot(lots of braking), and then put the brakes on HARD a few times. If it seems to go away a bit, keep doing it. Just make sure you don't come to a complete stop and leave the brakes on, as this will negate any benefits of doing this.

Hey, it's free, and worth a try.
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Old 09-08-2003, 07:18 PM   #21
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Quote:
Originally posted by BoardRider
I know it has been a while but I still haven't made it to the shop to get my brakes checked. Busy!!! But I did call them last Friday and the guy told me that he wouldn't turn the rotors on my car because of the way that the Subaru rotors (for my car?) are produced (material, heat treated, etc.). He said because of that, he won't turn them and that I would have to buy new ones.

Has anyone ever heard of this?

Also, what is the minimum rotor thickness (97 GT)?

Thanks!
That is absurd! time for a new shop.
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Old 09-08-2003, 08:24 PM   #22
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^^^

Agreed!

"Good grief" as Charley Brown would say.

That's the first time I've heard about that and I'd ask that "shop" to show you that in writing because I seriously doubt that a good Subaru tech or any brake tech that's familiar with Subaru's will tell you.

Br, Dale
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Old 09-08-2003, 11:19 PM   #23
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That's what I THOUGHT was wrong with my 98 Legacy - I went for a couple spirited drives a while back and I must have left uneven pad material while doing it, and so I've been getting pulsing sounds from the brakes.

So then I took my Legacy onto Gateway International Raceway. On the gutter before turn 1, got it up to 90 mph, SLAMMED on the brakes for turn 1, got the most horrible pulsing I've ever experienced - I thought I was going to miss the turn! Well all went well and after about 3 laps of horrible brake abuse, the pulsing dissappeared! Went for another 3 hours on the racetrack and my brakes work as well as new!

Well, I enjoyed the feeling until a week later - went for more spirited STREET driving again, and left uneven deposits on the rotor So now I'm back to where I was - granted, not nearly as bad as before, but still there.

Maybe it's time to get better pads that don't leave so much stuff - cause my wheels sure get dirty real quick too! Any suggestions from anyone? I'm due for them soon anyway (esp. after the racetrack)

So here's another question - when you apply the parking brakes on our cars, does it clamp only the rear pads or the fronts also? I suspect some of us might be melting hot pads onto hot rotors after a spirited drive...


Quote:
Originally posted by Speedwagon
Well, if it's just pad material, you can try and 'clean' them first. Get them good and hot(lots of braking), and then put the brakes on HARD a few times. If it seems to go away a bit, keep doing it. Just make sure you don't come to a complete stop and leave the brakes on, as this will negate any benefits of doing this.

Hey, it's free, and worth a try.
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Old 09-09-2003, 01:08 AM   #24
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Parking brakes are only the rears.
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Old 09-09-2003, 02:13 AM   #25
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Quote:
Originally posted by jey
That's what I THOUGHT was wrong with my 98 Legacy - I went for a couple spirited drives a while back and I must have left uneven pad material while doing it, and so I've been getting pulsing sounds from the brakes.

So then I took my Legacy onto Gateway International Raceway. On the gutter before turn 1, got it up to 90 mph, SLAMMED on the brakes for turn 1, got the most horrible pulsing I've ever experienced - I thought I was going to miss the turn! Well all went well and after about 3 laps of horrible brake abuse, the pulsing dissappeared! Went for another 3 hours on the racetrack and my brakes work as well as new!

Well, I enjoyed the feeling until a week later - went for more spirited STREET driving again, and left uneven deposits on the rotor So now I'm back to where I was - granted, not nearly as bad as before, but still there.



i have done that too. Getting them nice and hot and removing the pad deposits, but being carefully not to actualy stop until they are cooled down to a point where they pad wont bond to the disk.
I think this is why peeps are always thinking they have warpage.
my 2 cents
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