What are caster bushings and what do they do?

What do people mean when they say they exchange their "bushings" or "bearings"? Something suspension wise..

It seems like people in the know talk about them amongst themselves, because it's not always a new topic that comes up for example, questions about alignment.

I am sorry for the completely general questions or witch hunt..

I can already tell I might not get any replies but I just thought I'd stick it out there and hope for the best.

-racecar fun

 

used to connect the various moving arms and pivot points to the chassis and other parts of the suspension. In order to minimize vibration, wear, and transmission of noise, they often incorporate flexible material such as rubber or polyurethane.

http://en.wikipedia.org/wiki/Bushing

unless i am mistaken, a bushing for your LCA is the same type of bushing used for the caster dial.

bearings refer to spherical bearings i think... they're used in replacement of the rubber or polyurethane. more solid... i think they help with steering response and limit camber change during hard cornering... i have no idea to what degree.

 

What he said.

The Caster bushing is the rear most bushing in the front lower control arms...if your looking at the wheel from the side of the car the caster is what controls where the wheel sits in the well from front to rear..
the more Caster you have the harder to turn the wheel but more stable for some people...From what I recall...

when they are talking about bearings they are talking about Spherical bearings which replace the rubber with all metal..

 

And this is what it looks like... kinda
But I hope yours doesn't look exactly like this one.
If you raise the car you should see the rubber part stretched out and not like in the picture.
If the rubber part is seperated form the steel outer liner the suspension pre-load is also changed.

The caster bushing is a bit more flexable because the bolt is not in the same line of the rotation of the arm (if you know what I mean).
The lower arm pivots around an axes, but the bolt is not in the same line, its perpendicular to it.

The slotted hole in the subframe allows the bushing to move inwards and outwards (in the width of the car).
It moves when you turn the bolt & nut with the excentric cams because they push against the "ridges" on the subrame.
That makes the part of the lower arm where the knuckle goes move forwards or backwards (because the front of the lower arm is a "fixed" point) and that changes caster - and changes camber too IIRC.



edit: added comments and re-write.

 

interesting... thanks for the information.