Brakes, Brakes, Brakes :(

[CJAY]

ok team,

I tried looking through the whole forum to see if anyone's talked about this but no luck.

Well, I had my front brake squealing issues a couple of months ago and told Lexus about it. They asked me to have my brake pads be replaced with genuine Lexus brakes. I guess the guy before me had installed an after-market brake pads and screwed it all up. So no, I had them replace the brake pads and I just noticed lately that every time I hit the brakes going from 30mph and up, the car shakes and it just doesn’t feel quite right.

What do you guys think the problem is? The squealing is gone but now the car shakes.. which is worse?

Please help

Thank you

[lenore]

Could be the brake pads werent broken in correctly, or the disk is warped, or the guide pins arent lubed, If you had it done at Lexus did they turn the disk when they replaced the pads? by the way the best way to break the pads in is too drive up to 25mph and brake firmly but not hard, then let go row forward, press the brake pedal again slowly but firmly. then drive a little way and repeat...then you are done. If they didnt torque the wheels nuts with a torque wrench after servicing the brakes they could have warped the disk...Then they would have to be turned or replaced...

[Cami]

CJ, If you only replaced your pads, consider having your rotors turned. The description of your problem is consistent with a "hot spot" on your rotor.

Cam

[smooth1]

Sounds like you have a couple contributing factors and the result is the shaking you feel. Lexus, along with alot of other manufactures, are using softer materials in favor of the higher performance levels these cars are now demanding. So from all I can figure is that they must have just thought that as a daily driver, it would only mean the current owner would have to replace the brakes maybe 2 more times over the life of the car. While yes, increasing the ownership costs, the performance boost would be well worth it. On the chalk board this looks great. As they have the benefit of research and countless engineers and scientists testing and pushing the limits of performance all the time. Then we enter the real world. So follow along real quick. Different discs use different alloys and are constructed with different goals in mind. For example, large trucks have temp. hardened discs (cryogenically treated) that are super compressed steel alloys and milled. These discs are designed and sized for stopping heavy loads and enduring high friction heat levels. On race cars they design the discs to be light, dissipate huge levels of heat quickly and can be made of other exotic materials such as the new carbon ceramic materials. The pads that are used today range from metallic, semi-metallic, ceramic, and also come in all different levels of hardness, and friction levels to adjust initial bite, brake feel, and heat dissapation. So some consumer "mechanic" comes along and thinks that they can "boost" the brake performance by getting XXX superbrand brake and puts way to high a friction pad on a way to soft a disc and problems begin. The next issue is each of the brake system components are designed to work with each other. If you put new pads on a used disc, then you have just assigned the new parts to addtional and accelerated wear, as the new parts will "wear in" to match the used parts around it. The used disc doesn't become newer when you replace the pad. So, it sounds to me like the previous owner wrecked the discs by putting some mismatched brake pads on your car before you bought it. Then you put new brake pads on those previously damaged discs. And now when you hit your brakes you get a shake feel. Sounds pretty reasonable to me.

[lenore]

might just be build up on the disk, I have had success of taking emery paper and doing a once over in circular motion around the entire disk surface, front and back...takes the debris off. Then make sure your guide pins are lubed, and also the tabs where the pads touch the caliper mounting hardware...Cheap try to your problem..If it doesnt work than replace the disk...