Mechanics

ROTORS

2006 Lexus GS 300

Brakes problem
2006 Lexus GS 300 6 cyl All Wheel Drive Automatic 90000 miles

I have a 2 part question:
1) Do rotors always need to be changed or resurfaced when installing new brake pads?

2) My brake pads are 30,000 miles old. I had aftermarket front brake pads and shims installed. The front shims shifted out of position twice, coming in contact with the rotor hub and made a scrapping noise. The mechanic removed the shims recently, but I still hear a slight clicking once in a while when I come to a complete stop. There appears to be a tacky black paste on the back of the brake pads.

I believe the sound I am hearing are the front brake pads occasionally moving when I stop my car. What can I do to remedy this problem?
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Aaronac8
March 15, 2009.




Yes, rotors should be turned or replaced.
Turning; should only be done if after they are machined they are still in thickness specs. Also, if the rotor is slightly warped, turning will take the warp out and gives the new pads a fresh surface to start on. IF, you install new pads on a worn rotor, by the time the pad/rotor surfaces mate you will have lost 20-30% of the new pads life.

Replacing: With todays new pad materials, usually, when the pads are shot-so are the rotors and should be replaced with the pads.
The black sticky stuff you're seeing is probably silicone used as a vibration(anti-noise) supression product usually supplied with a new set of pads. Some shops use it, some don't. The squeaking your hearing during a stop may be from a slightly warped rotor, moving the caliper back and forth. Hope this helps.
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Tiny
James W.
Mar 15, 2009.
Wouldn't I feel a pedal vibration if the rotor was warped?

Tiny
Aaronac8
Mar 15, 2009.
Yes, if there was a wide or narrow spot on the rotor. If it's warped a little bit out of line, you won't. It will just move the caliper back and forth on the holder

Tiny
James W.
Mar 15, 2009.
Do I need to replace the rotor and brake pads now? Is this condition dangerous?

Tiny
Aaronac8
Mar 15, 2009.
Other than the fact the noise might be a little irritating, there's no danger. After market pads will usually offer a choice for something like a Lexus. Better and Best. Either one is equal in guality to what the dealers offer. Your brake noise may even go away in time. I it does, per chance, get worse you can change at any time. At this point, I wouldn't worry about it.

Tiny
James W.
Mar 15, 2009.

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