For those with suspension knowledge or have replaced their caster arm or bushings
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I have a 99 gs400 that is creeping up toward 160k. It has type flex coilovers and 20 inch staggered L-sportlines. The upper and lower control arms were replaced at around 120k when I got the car, ball joints included.
However, I have a decent shake at highway speeds. I could live with just the shake, but when brakes are lightly applied it turns into a death shake. More brakes= no shake. All of the shake is in the steering wheel and none in the pedal. All four rotors and pads have been replaced and to no avail. The bad shake only happens when tail gating someone and scrubbing speed or slowing down on an exit ramp. Like I said before, if you mash the brakes, no problem.
I am thinking that the caster bushings need replacement, but before I throw money at it, I wanted more opinions. When inspecting the bushings, they look fine, no rot or cracks and still soft. However, when using a pry bar it seems pretty easy to get the arm to move up and down at the bushing. Is this normal or should the arm be stiff at the mount/bushing?
Just to reiterate, the shake is not a vibration, but violent and scary. IT does not matter which wheels, but seems worse with bigger ones. I about to mount my gopro under the suspension and go for a ride to get a look at whats going on.
However, I have a decent shake at highway speeds. I could live with just the shake, but when brakes are lightly applied it turns into a death shake. More brakes= no shake. All of the shake is in the steering wheel and none in the pedal. All four rotors and pads have been replaced and to no avail. The bad shake only happens when tail gating someone and scrubbing speed or slowing down on an exit ramp. Like I said before, if you mash the brakes, no problem.
I am thinking that the caster bushings need replacement, but before I throw money at it, I wanted more opinions. When inspecting the bushings, they look fine, no rot or cracks and still soft. However, when using a pry bar it seems pretty easy to get the arm to move up and down at the bushing. Is this normal or should the arm be stiff at the mount/bushing?
Just to reiterate, the shake is not a vibration, but violent and scary. IT does not matter which wheels, but seems worse with bigger ones. I about to mount my gopro under the suspension and go for a ride to get a look at whats going on.
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Not sure what to tell you. My caster would be out of spec whenever i got an alignment. Replaced the entire arms (only way to get oem bushings) caster went back into spec. 2nd time they've been replaced, previous owner had them changed also. My bushings did not look bad when replaced. Easiest way to tell they are faulty is by the alignment specs. My highway steering wheel vibration decreased some, but i never had shaking under braking. I really would check the braking system including the calipers and rotors again. Sounds like they are the culrit.
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Ok, so I wasn't completely honest. This is far from my first rodeo, but I don't recall ever having a bad bushing in an control arm that is attached in this way and angle. What I want to know is what direction of movement would be transferred into the suspension while lightly braking, if a caster bushing was bad on these specific cars.
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not sure what to tell you. my caster would be out of spec whenever i got an alignment. replaced the entire arms (only way to get oem bushings) caster went back into spec. 2nd time they've been replaced, previous only had them changed also. my bushings did not look bad when replaced. easiest way to tell them are faulty is by the alignment specs. my highway steering wheel vibration decreased some, but i never had shaking under braking. i really would check the braking system including the calipers and rotors again. sounds like they are the culrit.
The one thing that keeps me leaving the thoughts of brakes is that the shake is amplified with larger wheels. That makes me go back to suspension due to leverage forces.
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I just did caster bushings over the weekend. My symptoms were the car being all over the place when changing lanes on the highway as well as a considerable shaking at highway speeds. Got the carson caster bushings, the shaking is completely gone, but it still pulls a bit when changing lanes.
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#9
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I have the exact same problem, seem like when im at speed and I dont let the suspension settle after making a lane change or something the steering wheel will shake with light pressure on the brakes, increase the brake pressure and it goes away or if i coast a bit and let the suspension settle it will not do it at all. I am thinking my caster arm bushing also, it is not the brakes I suspect because I do not feel pulsation in the pedal. anyone else have this problem and found a fix?
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I replaced the upper, lower arms, LBJ, tie rods, sway links which helped A LOT when this happened to me but I still have slight shaking in the steering wheel and none on the brake pedal and the same symptoms as everyone else. I just ordered 4 new rotors and hopefully that'll get rid of the shaking completely. If you want to make sure its not your rotors jack each corner up one at a time and try to spin the wheel if its free then you're probably good but if it sticks with no brake applied or it gets stuck on one while spinning then ya your rotors are warped
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Pull it all apart and inspect it... jack up the wheels and move them around rather than postulating about how you think the suspension works. I find that if I don't troubleshoot I almost always buy the wrong part... Don't forget to give the engine mounts a good look too.... There is a procedure in the manual on how to check the whole suspension...
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