Do I need to replace my rotors?


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Old 03-27-17, 09:57 AM
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Do I need to replace my rotors?

The braking surface seems alright, but the edges are pretty badly rusted. Here's some photos.

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Old 03-27-17, 10:16 AM
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The rust doesn't really mean anything. The important part is if there are grooves in the braking area. You can have them turned unless the grooves are too deep or the rotor is warped enough where once everything is right the rotor becomes too thin.
 
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Old 03-27-17, 11:49 AM
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What that indicates is a pad that has seen many better days and has chunks broken off to the extent it's not touching the rotor and providing braking.

There is really not much you are going to do to fix short of new rotors and pads. When you get that much rust you wont be able to turn them enough to remove.

If the pulsation is not so bad just run it till it gives way then fix everything.
 
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Old 03-27-17, 12:58 PM
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Yes, Junk them. You will be better off with new ones. New pads, new rotors.
 
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Old 03-27-17, 06:30 PM
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I didn't think rust mattered (aren't all rotors rusted?), but the mechanic was quite insistent that it does and that the vehicle is unsafe to drive like this. The brakes work fine, so I just wanted to get some opinions from people who don't stand to make any money either way.
 
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Old 03-28-17, 03:08 AM
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I've gone many miles with rust on the outer edge and cooling fins with no ill effects. I'd be more concerned with grooves in the braking surface and whether or not the rotor is warped.
 
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Old 03-28-17, 03:55 AM
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I find the biggest culprit in this type situation is not the rotor itself, nor the pads, but the caliper not moving properly. I see no evidence that the pads have even touched the rotor in a long while. I know it is expensive, but I would replace all three components. Braking is too important to do it piecemeal.
 
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Old 03-28-17, 04:37 AM
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I don't see the OP's location, but that looks like road salt cancer. I, too, would not worry about rust on the outer edges, but on the shot where you can see to the gaps between the inner and outer disks the corrosion looks pretty extensive. Replace them; prices on aftermarket rotors nowadays are so low as to almost make replacement over turning the way to go.
 
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Old 03-28-17, 04:38 AM
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That rust around the very edge of the rotor doesnt effect anything. The pads dont contact that edge. As for the area the pads do make contact, I see some groves in there that need to be gauged for the depth.
You can pull the rotors off, take them to most any parts house like Napa, O'Riely's, Auto Zone etc & they can put a gauge on it & tell you if they can be turned or if you need new ones. They at minimum need to be turned. When turning the rotors, they will turn them all the way out to the edge of the rotor which will get that rust on the edge & remove it anyway.
So:
1) if they can be turned, the rust will be gone,
2) if they cant be turned, you will need new rotors & the rust will be gone.
Either way, your question about the rust around the edge is going to be a non-concern in this case. Either way the situation will take care of the rust in itself.

I agree with chandler that your caliper doesnt appear to be working correctly & needs to be addressed as well. As Chandler noted, it doesnt appear to be contacting the rotor with even remotely enough force. That rust in the center of the rotor will also be taken care of with turning or new.

Just take them to the parts house & let them tell you. Then you know.
 
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Old 03-28-17, 04:39 AM
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Had a second look at the pics and am inclined to agree with Larry, perhaps the calipers should go, too. Kind of depends on how long you'll have the car.
 
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Old 03-28-17, 05:34 AM
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You have to keep the slider pins clean & lubricated or the callipers will bind up.
I live near the Motor City and we are in the rust belt. I remove, clean and lube the caliper pins yearly.
It is an easy thing to do when you are doing your regular tire rotations.
I would check the cost of rotor turning vs. rotor replacement - there is a lot of life left in your rotors
 
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Old 03-28-17, 06:59 AM
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Rotors are pretty cheap. I would replace them.

Otherwise have them turned at a reputable big chain auto parts store or automotive repair facility. These businesses do everything by the book and will refuse to turn them if it is not safe to do so - because they would then be too thin or some other problem. So not too much to turn them, but also you get expert advice as to if you should turn them or replace them.

And the reason big chains are so picky about things like brake work, is they do not want to be sued if someone's brakes fail. So they do everything to manufacturer's specifications - or not at all.
 
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Old 03-28-17, 07:19 AM
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This thread reminds me of a Brake Issue I had on my Volvo S60 just last year.

I had a pulsating pedal and had discussed it with a few mechanics who all said it was a "warped rotor". This was in spite of all four Rotors appearing all shiny and smooth (except for one little spot on a rear one.

I bought new pads and rotors for both front and back. Changed the rear first because there was that small rust spot present on the surface of the Rotor . . . . the result was NO CHANGE, the pulsation was still there.

Then I attacked the front Rotors. They looked better than the rears; but there was a little slaking rust along the inner circumference of the braking surface on one side. It wasn't the entire 360 degree circle; only about half of it. Then I looked at the corresponding Pad . . . . and sure enough, there was a torn up section of the Pad right where it would have been encountering the crusty slaking rust material.

I put on the New Rotors and Pads . . . . and no more Pulsation. Then I took the questionable Rotor to a guy who turns Rotors and Drums, and he verified that the Rotor was still true, AFTER he took a Ball Peen Hammer and pulverized the remaining portion of the rust on that inner circle of the braking surface. It broke right off. I could have continued using those Rotors once the slaking rust ring had been broken off . . . . it may have even been possible to knock it off of the Rotor while it was still mounted, using a blunt object to hit it at the right angle.
 
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Old 03-28-17, 08:58 AM
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Check pads

The rotors edges are normal for a salty environment. The pad surface looks a bit rusty too, that would suggest the pad is not making full contact, or perhaps your car was sitting in the wet before you took the picture, rust forms almost immediately on raw cast iron. But it does not look that bad, all rotors tend to wear with some grooving on the surface.

Check the pad thickness, you should be able to see it while the wheel is off, it should be at least 3mm thick, otherwise time to replace pads. It is also possible the caliper pins can seize up, there is a little rubber boot around the bolt (visible in the picture), which is supposed to keep moisture out, but in a harsh salt environment it can still get corroded. That said, a sticky caliper usually does not release fully, and you get smoke and such from a sticking brake while driving. So I suspect you are ok on the caliper.

So check the pad thickness, and do a few hard stops to make sure the brakes work well, and this will also clean off the rust on the friction surface. Should be ok if the pad thickness is there.

Brakes parts are very cheap these days, and most garages want you to be safe, so replacing things even if there is some service life left is not necessarily poor advice. But the rotor rust would not be the prime issue, its the pads and caliper that are the key. Might want to clarify the advice given, they might have just said they are rusty to avoid the need to give a detailed explanation of what underpins the recommendation. Once you are doing pads and lubing calipers (or replacing with rebuilt, if the originals are older ten years), replacing the rotors makes sense so you start with a fresh new set up.
 
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Old 03-28-17, 02:32 PM
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A little tip when replacing pads. Get the caliper bracket clean where the hardware goes. Rust builds up in the place the hardware fits into and will pinch the pad slots on the hardware a little causing the pads not to slide freely. I have a mini sand blasting cabinet and I clean then up like new and the hardware doesn't have to be forced in. When I install the pads with caliper lube they slide very freely in the groves. Just put some tape over the holes where the pins go to keep them clean. Most garages don't do this but there are a few that do.
 
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Old 03-28-17, 04:08 PM
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The pad surface looks a bit rusty too, that would suggest the pad is not making full contact, or perhaps your car was sitting in the wet before you took the picture, rust forms almost immediately on raw cast iron.
Yeah it had been sitting for a few days, maybe up to a week. I didn't take it in because anything was wrong, it brakes fine. I just had to do the yearly inspection and he failed it for "rusty rotors" (its even on the inspection sheet that way) and said I needed to pay $700 for new rotors and pads all around. Just trying to be sure I am not crazy before I have to deal with the government to fight this bs.
 
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Old 03-29-17, 02:13 AM
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From what your picture shows those brakes need service so I wouldn't waste my time fighting it.
Sounds like someone wants to make some money.
Shop around for other quotes for that job.
 
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Old 03-29-17, 03:23 AM
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Replacing the pads and rotor isn't a difficult job [or calipers, brake hose] if you'd like to diy. We can walk you thru it. Repair manuals can be helpful and I'm sure there is a video or dozen on the internet showing it done.
 
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Old 03-29-17, 03:28 AM
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Just for info, OP is in New Brunswick Canada.
 
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Old 03-29-17, 04:59 AM
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"I just had to do the yearly inspection and he failed it for "rusty rotors""

Take it to another place where they won't fail it.
Iím in Ontario and have passed many inspections with worse rotors than that.
 
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Old 03-29-17, 07:45 AM
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From what your picture shows those brakes need service
Can you be more specific? What exactly shows that? I get the advice to just swap them out if I were having a problem, but the consensus seems to be that if there's no actual problem to solve then there's no need to replace them.

Replacing the pads and rotor isn't a difficult job [or calipers, brake hose] if you'd like to diy.
Oh yeah, I'll definitely be doing it myself if I do it. I'm still not sure if I should spend the $300 on parts or just gamble another inspection someplace else.
 
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Old 03-29-17, 08:16 AM
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$300 sounds a little high for parts. Do you just have discs on the front or do you need to do all 4?
 
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Old 03-29-17, 12:00 PM
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He said all 4. Just got back from driving it and checked again and the braking surface looks nice and clean and blackish.
 
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Old 03-29-17, 06:50 PM
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Grooves and rust on pad surface of rotor.
You might have a stuck pad.
One look at you picture shows a problem.
They need service.
Walk around a parking lot and look at other vehicles rotors.
For the most part they will be shinny and no grooves where the pads make contact when brakes are working and wearing properly.
When you see rusty spots where the pads rub on the rotor and grooves that is a sign of something is wrong.
If you take that side apart I bet you will find a pad stuck in the caliper or part of the pad surface broken away.
I know if that was my car and my rotor looked like it does in your picture I would take it apart and look for the problem but that's just me.
 
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Old 03-30-17, 02:41 AM
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think I would replace the pads and rotors also, and make sure calipers are floating on there pins and not froze up. the rust looks bad but if the vehicle does not get drove very often I can see how it could eventually get that way, with the brakes not being used frequently enough to keep the surface clean.
might shop around online for parts also if your not in that big of a hurry to fix, you can usually find parts a lot cheaper online compared to local parts store.
 
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Old 03-30-17, 10:36 AM
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When you see rusty spots where the pads rub on the rotor and grooves that is a sign of something is wrong.
You mean the light surface rust coming up from the center in the last photo? That's just from sitting for a few days. After driving that's not there, its just blackish and shiny.
 
 

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