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Discussion Starter · #1 ·
Hello all was wondering if anyone had the same issue. I installed new centric rotors on the front and hawk hps pads on both axels. Had rear rotors inspected and they are good. Around 75mph and up major vibration occurs. What could it be or did I do something wrong this is the first brake job on the car and it has only 32k on it. Before doing the brake job I had pulsation but only during stopping now at high speeds.
 

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These cars seem very sensitive to the smallest imbalance. Did you index the front rotors and mark the rears so that they went back on the same way they came off if you removed them?
 

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Phil24....what work did the shop do? Did they index the rotors...please elaborate. I bought my G8 used...and it has the 75mph steering wheel shake when I press the brakes.

Thanks.
 

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Did you do the proper bedding process and properly re-torque the wheels? Just trying to eliminate causes. One of the brackets may have come slightly off it's position as well. I'd pull the wheels off and recheck everything.
 

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Yep, they got indexed. Also had new ceramic pads installed. If you bought it used with the shake, it could be a simple problem like warping. That's how my problems started. Bought mine used last year with 22,000 miles. Also got them resurfaced, turned etc.
 

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Discussion Starter · #7 ·
I did the proper bedding process and retorque still the same issue. What exactly is indexing?
 

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I just re-read your first post. Are you saying the car now shimmies WITHOUT applying the brakes at 70+mph?
 

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Discussion Starter · #10 ·
Yes only around 70 and above
 

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Discussion Starter · #11 ·
Sorry not when braking just in general around 70 and above
 

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It sounds like something was missed during re-installation. I'd check the brackets to make sure they weren't bent or cracked, the tightness of the caliper bolts and that the pads are seated properly. Warped rotors wouldn't cause vibration when the car isn't braking.
 

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Discussion Starter · #14 ·
Ok thanks everyone for your help I'm going to trace my steps and see what happens
 

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the other thing that could be the vibration would be your wheels are out of balance. I had an issue where a weight came off and I have vibration at 70mph
 

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^^^^ That's my thought also. If one of the wheels (which had some or all of its balance weights take a hike) and end up back on the front, you would easily notice that condition. Especially if it had a fair amount of weights added to begin with. If a re-balance check of all the wheels can't be performed at this time, perhaps reversing the fronts with the rears will produce a corrective action for now.
 

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Mine is ONLY when brakes are applied hard from above 55mph or so.

It is smooth as glass with no shimmy at any speed (with no brakes applied.)

I guess mine has to be warped rotors. I may try indexing to see if that helps a bit. But will probably order new AC Delco rotors soon.
 

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Mine is ONLY when brakes are applied hard from above 55mph or so.

It is smooth as glass with no shimmy at any speed (with no brakes applied.)

I guess mine has to be warped rotors. I may try indexing to see if that helps a bit. But will probably order new AC Delco rotors soon.
Yes, you need your rotors turned. That will take care of the shimmy.
 

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I used to be a fan of turning rotors until I found out I could get a new set for about the same price the shop was charging to turn the old ones.
 

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Over torquing the lug nuts can cause the rotors to warp a bit as well.
 
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