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Old 11-21-2006, 09:50 AM   #1
mike_311
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Tire noise/ shaky brakes and wobble at high speeds

I have a 2002 grand am. I changed the brake pads last year, I have noticed within the past few months that the front tires wobble at high speeds, 60+ mph. Latley its been getting worse, but it doesn't do it all the time, mostly n the afternoon. Its noticeable at high speeds but the severity isn't constant. There is a severe wobble when I apply the brakes to decelerate from high speeds, but I don't notice it too much during normal around town driving. The front left tire (or that area) makes a rubbing noise when I make a left turn but only when applying the brakes. I can make a left turn with no problem but if I am slowing down quickly and cutting the wheel fairly tight I hear (and feel) this rubbing. Any ideas?
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Old 11-21-2006, 10:00 AM   #2
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Re: Tire noise/ shaky brakes and wobble at high speeds

Sounds like you warped your brake rotors, very common on these cars since I belive they put ceramic pads on from the factory. get your rotors turned & check to make sure you have enough brake pad left (or replace), should drive like brand new ... and if you replace the pads put on semi-metalic pads, less likely to warp the rotors ... see if this fixes the rubbing when turning, bet it does.
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Old 11-21-2006, 11:19 AM   #3
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Re: Tire noise/ shaky brakes and wobble at high speeds

if it is warped rotors you should notice a pulsating feeling in the brake pedal when youre on the brakes.
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Old 11-21-2006, 12:39 PM   #4
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Re: Tire noise/ shaky brakes and wobble at high speeds

Is this something I can do myself? I never taken the rotors off. Do I just need to get them recut? Or should I have someone look at it and have them do it? What kind of costs am I looking at?

Thanks.
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Old 11-21-2006, 01:48 PM   #5
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Re: Tire noise/ shaky brakes and wobble at high speeds

If you know how to change your brakes then you can pull the rotors off the car and take them to be turned down (murray's auto parts, maybe napa, or a machine shop can do them). to get the rotors off all you need to do is take the tires off & the calipers / caliper brackets (rear) off, then they pull right off the hubs. Please block the car up safely (jack stands) take all of the rotors off, have them turned & put everything back together (oh and check the pad life while your taking them off). call around to see who turns them before & how long it will take (last time I went to lunch & came back & they were done). to get them turned your looking at $6 -$8 a rotor, new ones usually run around $20-$40 each (only get new ones if yours can't be turned, and don't buy cheap autozone rotors, if you have enough money get good napa rotors, its worth it.) check the websites they will give you prices.

I assume you feel a pulsation on the brake pedal while stopping, if not take the car to a shop to have them diagnois the problem.
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Old 11-21-2006, 02:20 PM   #6
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Re: Tire noise/ shaky brakes and wobble at high speeds

I fixed my Grand Am with the same problem by just hand surfacing the rotors with 80 grit emory cloth and replacing the pads with some quality pads and breaking them in by getting them slightly hot and allowing them to cool several times. Also you do not want to get them real hot and keep the brakes engaged. What this does is it gets pad material embedded in the rotor surface and causes the pulsating sensation you feel. If you over torque the wheel lugs you can tweak them just enough to make them feel warped, just loosen them back off and retorque them.
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Old 11-21-2006, 04:02 PM   #7
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Re: Tire noise/ shaky brakes and wobble at high speeds

If your rotors are warped(theypulse when braking) they are not fixable.

as said above use high quality parts here, brakes are the most important thing on your car.

Also when the pads were replaced before, did you put them on right?
The wear indicator goes on the inside of the caliper.
If they are on wrong they will rub and wear your pads and rotors badly.

Warping can be caused by over tightening the lug nuts.
Should always torque them to 100ft lbs.
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Old 11-21-2006, 09:25 PM   #8
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Re: Tire noise/ shaky brakes and wobble at high speeds

I've had the exact same problem on my '02 Impala and '99 Grand Am (as described by mike 311) and fixed both of them as mentioned in the above post. Did not replace or turn the rotors I just hand surfaced them and replaced the pads. Both cars are fine now.
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Old 11-21-2006, 10:50 PM   #9
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Re: Tire noise/ shaky brakes and wobble at high speeds

mike_311,

If you get wobble at high speeds then your brakes have nothign to do with it, its your tires out of balance, and pretty bad from what you explained.

OR it could have a busted belt which will do the shaking to.
The colder it is the more the busted belt will make it wobble/shake.

You will always have some pulse when braking, that's what the ABS does.
But excessive shaking of the steering wheel while breaking isnt the normal when braking.

Most Napa's charge around $10 to resurface rotors.
Any place that can turn them, can measure them and tell you if they are to warped and or can be used.

crazy jim,

He is experiancing wobbles at 60MPH .
Most brake pad replacments require that you at least scuff up the rotors to remove the glaze.

IMO Turning them, for the small cost,
is much more effective on removing the glazing and trues them up even amoung the pairs
And stoping is so much better :just my
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Old 11-22-2006, 08:06 AM   #10
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Re: Tire noise/ shaky brakes and wobble at high speeds

Quote:
Originally Posted by xeroinfinity
mike_311,

You will always have some pulse when braking, that's what the ABS does.

crazy jim,

He is experiancing wobbles at 60MPH .
Most brake pad replacments require that you at least scuff up the rotors to remove the glaze.

IMO Turning them, for the small cost,
is much more effective on removing the glazing and trues them up even amoung the pairs
And stoping is so much better :just my
ABS pulse (ABS system cycling the pressurre on/off very rapidly) will only be felt if, while braking, at least one tire is detected by the sensor to be locked up and skidding.

I had the same exact symtoms as you and mike 311 have described ( My front tires would shake at 65 mph, under light braking I would feel a pulsing through the brake pedal (not the ABS activated) and under heavy braking the steering wheel, at times, would shake noticably. ). I did not say not to have the rotors turned but that I did not have to have them turned. As detailed earlier I hand surface them with 80 grit emory cloth, this, in essence, did "scuff" them up. This is usually a problem with material embedded in the rotor and/or the lugs to tight, both of which can be remedied at home in the driveway like I did mine. If you want to feel what the ABS actually feels like get the car out in a big wet parking lot or wide open empty street when it is wet and lock the tires up momentarily. This will activate the ABS system so you can get a feel for it.
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Old 11-22-2006, 09:07 AM   #11
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Re: Tire noise/ shaky brakes and wobble at high speeds

alright these post aren't helping Mike ... lets not make this into a personal thing ... were all saying the same thing ... we just have different approaches.

Mike if you only experience the woble when your on the brakes then you probably have warped rotors ... best way to solve it is turn the rotors ... can also be remedied by taking the glazing off the rotors with organic steel wool ... but I personally feel that your rotors have gotten too bad for this method, I recomend you have them turned. (since you said they have gotten worse over the last few months)

If you experience woble while driving down the road without using the brakes have the tires balanced ... they might be out of balance or have a broken cord in one them.
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Old 11-22-2006, 09:21 AM   #12
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Re: Tire noise/ shaky brakes and wobble at high speeds

Avoid ABS problems during routine brake service.
Motor Age; 2/1/2003; Buckley, Jay M.

Antilock braking systems (ABS) have had more of an impact on brake servicing than may seem obvious. And although most jobs are routine and your customer leaves satisfied, on occasion somebody will come back in to your shop with a complaint.
Most comebacks aren't the result of something intentionally done wrong, but may be caused by something being overlooked.
I get the following call at least once a day: "I just did a routine front brake reline and now the car's:
* ABS light is on.
* Brake pedal is low.
* Brakes are dragging.
* Pulling to the left/right."

These problems can be avoided by adopting some simple and very effective practices when performing brake service on an ABS-equipped vehicle. The number one cause on these problems is very simple, and to prevent it from happening, technicians need to modify the way they are currently doing a brake job.

It is extremely important to open the bleeder screw when compressing caliper pistons or wheel cylinders during routine brake maintenance. When a caliper piston is pushed in, brake fluid gets forced backward, up into the system. Since the caliper is the lowest point in the system, dirt and corrosion naturally accumulate there. When this grime and dirt finds its way into the HCU portion of the ABS system, it can cause valves to stick. This can lead to: a vehicle pulling one way or another; accumelators sticking open, which leads to low pedal; compensator ports pluging, which leads to dragging brakes; and of course, it can make the ABS light come on due to all of the above.

If technicians get in the habit of opening the bleeder when they compress the caliper piston, as well as selling customers a brake fluid flush, these problems will more than likely be prevented.

Another problem that concerns installers is when the ABS applies itself at low speed. Wheel speed sensors are magnetic. They can collect large amounts of debris from the road. Freshly turned rotors also can leave metal filings on the sensors, especially if an on-car brake lathe is used. The Honda Motor Go. actually recommends removing the sensors during rotor machining. We suggest cleaning the wheel speed sensors and tone rings during a brake job. This can help prevent false signals that can actuate the ABS system during low speed stops.

Brake technology, like everything else automotive, is changing constantly. By keeping up on changes like these, you're likely to avoid unneeded comebacks.
Jay M. Buckley Bendix Answerman and Brake Training Administrator Honeywell Friction Materials



Remedy For Pulsing Brakes.

Popular Mechanics; 2/1/1999; WEISSLER, PAUL

Pulsating automobile brakes is a problem that needs attention, beginning with finding the source of the problem. A common cause of brake pulsation is uneven lug nut torque, in which the torque difference should be no more than 20% between each lug nut. Steps for a complete inspection and remedies are described.
The driver in the left lane suddenly realizes he's about to miss his exit, so he cuts in front of you. You mash the brake pedal, and it vibrates like a running chain saw as the antilock braking system (ABS) keeps you out of a skid. Thankfully, you don't rear-end the jerk's car, as he also brakes to slow down. He's on the off ramp and gone, so you don't get the chance to pull alongside and express your feelings with universal sign language. But that's probably a good thing.
While it can be reassuring to feel that ABS-connected brake pedal pulsating beneath your firmly planted foot, it's reason to suspect a problem if you get the same pedal pulsation with a light to medium braking application.



ABS-esque
If the brake feels like the ABS is cycling, but you know that it's not, check the individual axle trigger wheels in front (and on some cars also in back) and the adjacent wheel speed sensors. If you see a damaged wiring connector, bent sensor mounting bracket or stone-damaged trigger wheel, that's a likely cause. But on almost all cars, the cause normally is something in the service brake itself, and the primary problems are ones you usually can check and correct yourself.

The No. 1 cause of brake pedal pulsation is uneven lug nut torque. The usual reason is that some mechanic overtightened the wheel lug nuts with an impact wrench, distorting the brake disc.

How do you know if your torque wrench is accurate?
Well, if it's by a name-brand tool company and hasn't been thrown around or had a cement block dropped on it, it should be okay. Check the torque at each wheel and compare the reading with manufacturer's specifications.
If there's a difference of 20% between any two lug nuts, that's too much. Try loosening all the lug nuts, cleaning the stud threads with a wire brush, lightly coating them and the nut chamfer with clean engine oil, and then reinstalling the nuts fingertight.

Next, using a crisscross pattern, tighten all of them to about one-third the specified reading, then to two-thirds and finally to the specified torque.


Eliminating disc brake noise.

The most common complaint after disc brake service is noise, and brake pads are often singled out as the cause. However, the majority of brake noise is not generated by the friction material. It is caused by vibration of a brake component that is not properly installed, insulated, secured or lubricated. Here are some points to keep in mind for your next brake service job:

* Shims: The two most common types of shims are a woven fiberglass cloth impregnated with rubber or a thin wafer of steel coated with plastic. These shims tend to shift during the life of the brake lining, resulting in noise. To correct this problem, the latest generation of shims has a Nitrile Phenolic dampening layer sandwiched in between two thin wafers of steel. Most importantly, they have a heat-activated adhesive to bond the shim during initial use. Disc brake shims should not be reused.

* Insulators: On sliding, floating or fixed-style calipers, disc pads must use an insulator between the pad and/or the piston and caliper housing. The most common insulators are spray or paste coatings applied to the back of the pad prior to installation. Over time, these insulators have a tendency to break down, allowing metal-to-metal contact between the pad and the caliper housing or the piston. The result is noise.

* Lubrication: Inspect old linings for any shiny areas where any metal surface came in contact with the caliper housing, piston or steering knuckle. Clean these areas thoroughly. It may be necessary to use an abrasive such as emery cloth to remove heavy deposits of rust. Apply a light coating of Moly paste brake lubricant to these same locations and to the shim/caliper.

* Rubber components: Replace all rubber components on the caliper and lubricate them with silicone-based high-temp lubricant. Do not use petroleum-based lubricants. Rubber components absorb vibration and change the harmonics, dampening grinding and squealing brake noise.
* Hardware: Install and lubricate new mounting hardware even if the old hardware appears to be in good shape. Constant heating and cooling can weaken metal hardware components and make rubber parts less resilient. Weak hardware causes excessive caliper/pad movement, causing noise, uneven and premature pad wear, overheating of pads and rotors, rotor warpage, pulling and poor stopping ability.

* Rotors: If not replaced, rotors must be machined. A rough surface finish contributes to noise and poor braking ability. Once the rotor is machined, a non-directional surface finish procedure is recommended. Use a sanding block with 120- to 150-grit sandpaper. Work the sanding block up and down for about one minute per side, while applying a medium amount of pressure. Before installing, clean the rotor thoroughly with soap and water so that the fine metal particles from the machining process do not become imbedded in the new brake pads, resulting in noise. Lathe operation and maintenance is crucial to obtaining a good surface finish.

* Break in: Repeated hard stopping or abusive driving should be avoided with new friction material.
It is normal under certain conditions to have nominal brake noise, as stated in some OEM factory-issued service bulletins. However, the utilization of these service tips will minimize brake noise and reduce customer complaints.


Quote:
Originally Posted by crazy_jim
As detailed earlier I hand surface them with 80 grit emory cloth, this, in essence, did "scuff" them up. This is usually a problem with material embedded in the rotor and/or the lugs to tight, both of which can be remedied at home in the driveway like I did mine.
Scuffing the rotors with 80 grit will not fix the pulse feeling or wheel shake.

Materials dont really get embeded into the rotors.
Just glazed and or groves.
If you have materials embedded in your rotors, then they have been overheated and softened the steel to allow this to happen.
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Old 11-22-2006, 05:55 PM   #13
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Re: Tire noise/ shaky brakes and wobble at high speeds

Excellent write up Xeroin, as for my simple procedure, it did cure my brake/shake problem. May not help everybodies but I figured I'd outline exactly what I did to work out my prob.
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Old 11-24-2006, 12:43 AM   #14
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Re: Tire noise/ shaky brakes and wobble at high speeds

it could be the alingment too
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Old 11-25-2006, 08:54 AM   #15
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Re: Tire noise/ shaky brakes and wobble at high speeds

Quote:
Originally Posted by thatotherguy186
it could be the alingment too
Brake pulse or shaking at speed has nothing to do with alignment.
Read the article outlined above!
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