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A year ago I replaced the front rotors & pads on my wife’s 2008 Town & Country (Touring 3.8L w/ 132k mostly highway miles) after the steering wheel began vibrating and the pedal pulsed when braking. I used Centric Premium rotors (& Posi-quiet pads), the same brand I had put on 2-3 years before. That took care of the problem — braking has been smooth as glass — but now the same vibrating is showing up again, barely a year later.
My wife is a conservative driver — certainly not hard on the brakes — and I’m careful about torquing the lug nuts and checking torque after anyone else touches the wheels. I’ve used the same model Centric rotors on all of our cars for 4-5 years without any other problem, so this is a puzzle. Any thoughts or similar experience? I’d be surprised if OE rotors were longer lasting, and would rather not pay up for them — but then I’d hate to have to do this year after year…
Thanks in advance.
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Rotor warping…
There are two views on this issue..
First:
[color=orange]Brake rotors do not warp from heat, even when driven by the most aggressive traffic officer. Instead, they wear unevenly. This uneven wear is caused by the brake pads themselves as they intermittently touch an out-of-true rotor. The root cause of the uneven wear is one of two things: either the rotor was installed out-of-true with the hub, or the tire was improperly torqued to the hub during the last tire change.All of this is important for fleet managers because their vehicles have the tires removed frequently and the pads and rotors replaced frequently. You won’t solve a problem caused by wear if you treat it as a problem caused by heat. Instead, fix the rotor installation or wheel lug nut torquing.
The problem of pedal vibration, incorrectly called rotor warp, occurs 3,000 to 5,000 miles after the brake or tire change. Because it is caused by uneven rotor wear, not the rotor warping like a potato chip from heat, you can’t solve this wear problem by better control of the heat, i.e., by the use of specially processed rotors or drilled and slotted rotors. Instead, you solve the wear problem by fixing the shortcuts in rotor installation or the improper lug nut tightening.
By taking a few steps, the fleet manager can easily, quickly and permanently fix the pedal pulsation problem. First, for each rotor change, verify the runout of the rotor, and then do one or two quick things to have it less than 0.002 inch, which is the OE spec for most vehicles. Two, for each tire and wheel change or rotation, torque the lugs in a star pattern using either a torque wrench or torque stick. Those two steps will virtually eliminate premature rotor wear, period.
Think about it this way: What are your conservative officers doing to their cars to “warp” the brake rotors in less than 5,000 miles? They don’t get the brakes warm (350 F), let alone patrol-hot (600 F), and never pursuit-hot (850 F). Yet their rotors are warping? No. They are not warping. They are unevenly wearing during the times of zero brake pedal pressure, and your officers are not doing anything to either prevent it or cause it.[/color]
Other info:
http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-mythsSecond:
[color=orange]What causes warped rotors?
Most of the time, warped rotors are caused by excessive heating. What’s causing the excessive heating? A technician would need to run some tests to diagnose the cause, but it could be a few things:
Brake system issues
If your back brakes aren’t working, for example, your front brakes will work even harder, heating up your rotors. Or maybe you’ve got a sticky caliper (the mechanism that houses and operates your brake pads).
Note: If your shocks are not performing as designed, they can also be the root cause of rotor warpage as excessive weight shifts to the front design braking.
Driving habits
If you live in a city where you’re hard on your brakes either because of the hilly terrain or the traffic, it can take a toll on the performance of your brake system.
Over-torqueing
Any time you have a wheel installed and someone hasn’t torqued your wheel up properly, that can put stress on your rotor.Any one of these problems can lead to the excessive heating that’s warping your rotor. Rotors are a cast metal and the heat generated by braking can release the stress of the casting. That’s when your rotors will warp, especially if they’re thin from wear. You might not be able to see your warped rotors, but you’ll probably be able to feel it.
How to tell if you have warped rotorsRotors are normally flat and smooth, and as the brake pads clamp down on them, your wheels stop. When they’re warped, your brake pads can’t clamp your rotor as easily. That’s why you’ll feel a shudder on the brake pedal when you try to stop, especially at high speeds when your rotors are rotating faster.
You might notice a vibration on the steering wheel as well, especially if it’s your front rotors that are warped. The more warped your rotor is, the more severely you’ll feel that shake on your foot or your hands.
What can you do if you have warped rotors?You have two choices: replace them, or machine them. Warped rotors, if they’re thick enough, can be turned in a machining process that uses a lathe to smooth the rotor. Unfortunately, since it’s a stressed metal, your rotor can return to its old, warped shape[/color]
My suggestion is to confirm what is actually happening.
Are the rotors actually out of flat/round or is it a pad issue.Thanks flyr — thinking through these possibilities —
1) I can’t imagine my wife in hot pursuit 🙂
2) It’s unlikely the front brakes are having to compensate for inadequate rear braking — both rear brakes have fairly new OE calipers and I service them regularly.
3) I wire-wheel the hub faces when changing rotors, and use a torque wrench with star pattern on lug nuts (although I’m going to start using the Costco method of bringing the tire down to a few inches off the ground, then “chocking” and tightening before letting the full weight of the car down, to assure even tightening).
4) So any uneveness from then on would seem to have to result from uneven pad pressure (no evidence of uneven pad wear), unlikely overheating, or hub run-out.I’m thinking I’ll change one side at a time to find the offending rotor, check for uneven pad wear, then take the car with the new rotor to my mechanic to check for hub runout. I’ll let you know what I find.
Just a thought to keep in mind …
A odd occurrence:
My wife at the time..
We were driving along on a rainy day, just buzzin’ along.
Someone jumped out of one of the side roads right in front of us.
She laid into the brakes, cut the wheel to avoid the car and ended up in a huge puddle.
Right after that she mentioned that the brake peddle felt strange.
I switched places with her and sure enough You could feel it in the pedal and steering.
Rotors had warped due to high heat of a panic stop then rapid cooling when we ended up in a 14 inch deep puddle.She isn’t hard on her brakes either, but given the right conditions anything is possible.
Please keep us posted and good luck.
I’m just now posting the fix on this from a couple months ago: I put a runout gauge on each of the front rotors — driver side was > 0.004 inch, while the passenger side didn’t move the dial. I replaced the driver side rotor (with OE) and measured runout again, which was within 0.001. I just de-glazed the passenger side rotor, which was in good shape, changed and bedded in the pads, and the pulsating/vibrating disappeared.
Who’s to know what caused the runout, but my takeaway is to measure it before changing rotors.
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