Thank you everybody for your time!

I have a 2000 gs300. My front end will vibrate and shake when braking. More so at higher speeds, say coming off the highway.

To explain - I experienced a vibation in braking with the front end so I decided to change out the rotors.

I first changed my rotors with a slotted rotor which I bought from rotorexperts.com. They were 140.00 for the pair. With the replacement of the rotors - I, of course, changed the pads for a good semi mettalic from o'reillys. A mid stream cost pad. After rotor and pad replacement - My front end would vibrate still. so I purchased lower Ball joints and tie rod ends from rockauto.com. I got the higher end priced ball joints and tie rods.

After replacement of the ball joints and tie rods - I had a alignment and off I went. Well, I still have the vibration and I am dumbfounded !

Could any one PLEASE help and clue me with any sort of knowledge why I would still have a braking vibration ? ?

Thank you so very much.....

 

your on the right track, its your bushings, upper control arm, caster, etc... I have this too when i use the brake hard, if i let the car coast before using the brake lightly at first it does not do it. I am doing the steering rack bushing, sways bushing soon and see if it helps. I already did my lower ball joints with oem ones and that help with the steering feel but not the vibration when brakeing, I will try the Daizen bushing kit that address all the other bushings.

 

Sticking caliper?

 

I have similar problem of what you described, I change out my rotor and brake pad and the problem is gone, it turns out to be the pad that I have is tapering off on one side of the pad, and it happens on both side in the front(I don't know how did that can possilbly have happened, may be one of the two caliper pistons is stucked?), I use a C-clamp to push the pistons back in and it can move, so I don't know how did that happened.

But you said you changed both front rotors and pads and still seeing the problem, so my only suggestion is to open up the brake caliper, take out the pads, lightly push on the brake and see if both pistons on each caliper came out(there are two pistons in each caliper), use a c-clamp and push the piston back in, repeat this process a few times and see if the pistons will come out everytime. It could be one or more of your pistons in the caliper or guide pin are bad, so the force exert on the pads are not even, then, that will cause vibration when you brakes.. hope that helps.

I seriously doubt the vibration is caused by the supsension component, if it is, you should feel the vibration all the time, not just when you are braking.

 

Wheels have no cracks/bends? Possibility. But try upper control arms and bushings

 

Rotate the tires front to rear, rear to front to see if anything changes. Check to see if they are directional tires and mounted on the rims the correct way.

 

I went and bought all New tires this weekend. A set of high end yokohama's from discount! And the problem is still there.

Daihapp133 - you really think it could be a caliper problem? I can understand the two caliper system having one of the pistons not push at the same time - sure does seem logical. But I was told by a mechanic that the GS models were very picky in there suspension systems which could lead to vibrations and such when suspension parts tend to wear. He was the guy to say that this model was noturious for vibrations when the ball joints go.

I asked the tire installers if they saw anything and they said no. I am going to put it up today and look at the calipers.

 

Could be caster arm bushings ...........

 

I cannot comment on what your mechanic told you since there is a lot of them out there just want to makes up something and try to earn some extra $$ from people.

This is my thought, if it is your suspension, that you should feel the vibration all the time, sounds logical? Why would that vibrations happens only when you applies the brake? That just means there is something not right in the brake system.

Since you already changed your pads and rotor, and the only things left are:

1/.one or more of your brake caliper piston may be jammed
2/.Caliper guide pin is bent(replace pin) or seized.(new brake lube is needed)

These things are very easy to check. Take a look at it and report back to us what happened.

 

The rotors on this car can and will be ruined by a using an air driven impact driver when servicing wheels and tires.
They are susceptible to warping when over torqued.

For example; you take your car to get a set of new tires mounted on your existing wheels only to find out in a couple days you notice a vibration when braking.
These rotors have been known to warp for no other cause than mentioned. You didn't hit a curb, the suspension is just fine, warping can and will occur due to the lateral torque applied to the rotor by over torquing the mounting studs.
I don't even trust torque sticks for the Lexus, I want 'em hand torqued every time they're broken loose.

 

Good points. When I did the brake work - I hand torqued the wheels and the vibration was there so I am confident that the new rotors are not warped. I appileid the wheel lugs according to specs. The vibration is really showing up today when braking so I am putting the car up on a rack tomorrow morning....

I will post pics and updates soon as possible...

 

Sounds logical but may not necessarily be true. When dealing with rubber bushings the car may drive fine but when forces are introduced to (in this case the caster arm) under braking a worn bushing will give way and allow the part it is supposed to dampen, oscillate/vibrate. Get off the brake the worn bushing "sets" in its sagging position and no more vibration.

My car vibrates under high speed braking but not low speed (under 30mph) and I'll be swapping out my worn rubber caster arm bushings with L-Tuned polyurethane ones ... I'll report back when I get that done.

 

I got the poly caster bushings in today and I'm happy to report:

• vibration under high speed braking is 95% gone. There's a little shimmy but that might be because I actually need new rotors.

• no more clanking and clunking from the suspension going over speed bumps, into driveways, over expansion joints, going from reverse to drive ... etc.

• alignment "seemed straight with the old worn bushings ... now it's slightly to the right. Hopefully this will correct the ACCELERATED inner tire wear that I was happening.

 

Success !!! I took the front brakes apart today and found the rotors had a slight wobble to them. I had them machined and put them back on. The pads are brand new so I took a little sand paper to them with a flat block sander But the one thing I noticed and remembered front my previous install was these pads come stock without shims. So i took my used old shims and used them with my last install. A outer portion of the piston was missing them shim so I tossed the old shims and installed pads shimless. I used a silicone brake quiet but before install - I had a buddy tap the brakes so push the pistons out to check if any were stuck. All four pistons moved in and out so I install everything back -- And wobble gone!

All i can say is - The new internet rotors had a slight factory warp and the shims didn't help with vibrations.

I do know that all my bushing need replaced - just by inspection while working on brakes , I can see bad bushings abound. I also know that my struts are bad so I have some work to do!

Thanks everyone!