RX - 1st Gen (1999-2003) Discussion topics related to the 1999 -2003 RX300 models

Vehicle vibrates when pressing brakes

Old 07-19-07, 02:29 PM
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Shawnmack
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Default Vehicle vibrates when pressing brakes

I have a 2001 When I press the brake on the highway to slow down the vehicle vibrates and the steering wheel shakes like crazy it sounds like the rotors are warp could it be anything else?
Old 07-19-07, 02:31 PM
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Lexmex
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That's usually it the rotors. I have to turn/machine my fronts at least two times since I had them replaced.

Sometimes when the brake pads are really far down and you press on the brake, they can also jerk like this
Old 07-19-07, 02:58 PM
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miniround
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does this mean that i need new rotors now. crap. i knew my brakes were getting low...but now that I see this problem with your car and since i know i have it on mine...im thinkinng my rotors are warped. uhoh
Old 07-19-07, 03:00 PM
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I hope I don't have to buy new rotors my wife is getting ready to trade it in this fall.
Old 07-19-07, 03:00 PM
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Lexmex
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Originally Posted by miniround
does this mean that i need new rotors now. crap. i knew my brakes were getting low...but now that I see this problem with your car and since i know i have it on mine...im thinkinng my rotors are warped. uhoh
I tend to really abuse my brakes (the traffic is really something here), and it does indeed occur. You don't need to take this to a dealer...a lot of mechanics have the machine that can turn the rotors. Most of the time you just have to machine the fronts.
Old 07-20-07, 01:56 PM
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Originally Posted by Lexmex
I tend to really abuse my brakes (the traffic is really something here), and it does indeed occur. You don't need to take this to a dealer...a lot of mechanics have the machine that can turn the rotors. Most of the time you just have to machine the fronts.
So in other words I don't need to buy new rotors.
Old 07-20-07, 02:17 PM
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mandyfig
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Depending on how thick the rotors are....best thing is to take to a local mechanic and let them check rotors, if still ok, can be turned. Pads probably have to be replaced.
Old 07-20-07, 03:36 PM
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Originally Posted by mandyfig
Depending on how thick the rotors are....best thing is to take to a local mechanic and let them check rotors, if still ok, can be turned. Pads probably have to be replaced.
That's right. Check the pads first to see if they have any life left and if they still have life chances are highly like the rotors. Even if the pads don't have much life, you will know soon after changing them if you a rotor problem as you will feel the vibration.
Old 07-23-07, 12:17 AM
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TunedRX300
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Originally Posted by Shawnmack
So in other words I don't need to buy new rotors.
There is a misconception that brake rotor is "warped" as in change in shape but most of the time it is just uneven deposit of the brake pad material. See picture

Since you needs to replace front brake pads anyway, you can try this procedure to remove the uneven deposit.
http://www.stoptech.com/tech_info/wp_padremoval.shtml
If things don't work out, you still have the option of cutting rotors or replacing with new ones.
Old 08-19-07, 11:44 PM
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Just wondering..is this steering wheel vibration seen on other Lexus models as well? There seems to be a pretty good number of RX owners who have experienced this shaking problem, I wonder if this is seen across other models like the ES, IS, GX etc..
Old 08-20-07, 06:05 AM
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I think that rotor warping is common not only to Lexus models, but across cars with alloy wheels in general. When the wheels nuts are incorrectly torqued, you get rotor warping, in my opinion. There may be other reasons, but I think that is the main reason. Most tire stores I've checked out (only checked a few) don't even have the equipment to torque wheel nuts. Costco is an exception.
Old 08-22-07, 01:39 PM
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mandyfig
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What is the torque requirement for our wheel nuts? I bought a torque wrench for this purpose and have stopped using it for years. I just know that I have applied enough torque by experience and feel. But it is safe to calibrate your feeling to the right torque. Happens all the time, you put in an extra something....and it could really over torque it....but I do not understand clearly how it will induce warping...
Old 08-22-07, 01:42 PM
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DJ TANTRA
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i get vibration too is my 2001 gs430

it is a veryy common problem...

search it in the forums...steering vibration not only due to rotors but in general seems to be a very common problem :-\
Old 08-22-07, 02:19 PM
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Originally Posted by mandyfig
What is the torque requirement for our wheel nuts? ...but I do not understand clearly how it will induce warping...
As I recall, the torque for the wheel nuts is 76 ft-lb. I think it is the uneven tightening that is the real problem. I think this uneven pressure causes the rotors to warp. My last car (Made in the USA) had a much greater tendency to warp rotors than my RX. My mothers Lexus ES300 had the rotors warp, which I atribute to her taking it to the local tire shop to get a flat tire fixed. When I later checked, the mechanics there didn't even have any equipment to torque lug nuts with.
Old 08-22-07, 03:36 PM
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You are right the sequence of the pattern is crucial in making sure that the face of the wheel is parallel to the face of the hub. More critical than the torque. Over torque done in the right sequence (meaning not in one stroke), is ok than under torque. Costco screwed up my car 10 years ago, the nuts came off....fortunately I noticed in the nick of time. They also have destroyed one of my rims on my CRV, they had to pay me to get it to a restore shop, cost $215.

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