Front lower control arm bushing failure
11-27-2003, 08:17 PM
#1
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Thread Starter
Front lower control arm bushing failure
To recap from another thread:
http://forums.s2ki.com/forums/showthread.p...threadid=164579
About a month after Nationals, I drove the car on the street for the first time. I noticed I had the wheel quite a bit to the right to drive straight. My first thought was that the toe had simply drifted out. I thought a bit more about it, and how my toe has never drifted on this car, and decided I must have broke something.
It took about 30 secs to see that the left side rear lower control arm (LCA) bushing (caster bushing for lack of a better term) was not centered about the vertical bolt that locates it. Closer inspection revealed the rubber had torn, over lots of very hard braking cycles. I have no idea when, exactly, it tore. The right side bushing showed signs of the failure starting, but was still nearly centered on the bolt. I replaced it too.
So, the arm rotates back about the front bushing, looses a lot of caster, a bit of camber, and takes the wheel toward toe out (and thus having to steer to the right). It looks like this will be about an every 2 year replacement cycle. It showed up in my alignments over time too...lost about 0.1
http://forums.s2ki.com/forums/showthread.p...threadid=164579
About a month after Nationals, I drove the car on the street for the first time. I noticed I had the wheel quite a bit to the right to drive straight. My first thought was that the toe had simply drifted out. I thought a bit more about it, and how my toe has never drifted on this car, and decided I must have broke something.
It took about 30 secs to see that the left side rear lower control arm (LCA) bushing (caster bushing for lack of a better term) was not centered about the vertical bolt that locates it. Closer inspection revealed the rubber had torn, over lots of very hard braking cycles. I have no idea when, exactly, it tore. The right side bushing showed signs of the failure starting, but was still nearly centered on the bolt. I replaced it too.
So, the arm rotates back about the front bushing, looses a lot of caster, a bit of camber, and takes the wheel toward toe out (and thus having to steer to the right). It looks like this will be about an every 2 year replacement cycle. It showed up in my alignments over time too...lost about 0.1
11-28-2003, 06:00 AM
#2
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I just replaced the right rear hub and bearing at 18,000 miles.
The bearing spun on the hub... And me being the hammer mechanic on occasion I messed up the one ball joint that does not have a part # so I had to replace the knuckle too....
On the bright side it inspired me to get all the tools neccesary for doing the job properly.
The bearing spun on the hub... And me being the hammer mechanic on occasion I messed up the one ball joint that does not have a part # so I had to replace the knuckle too....
On the bright side it inspired me to get all the tools neccesary for doing the job properly.
11-28-2003, 10:34 AM
#6
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A metal speherical bearing. Replace the rubber w/ metal.
Its not something you'd want to do for a street car. You could get away with monoballing a few of the bushing like the one above on a street car w/o too much harshness, but they will transmit more of the road vibrations into the car. But metal flexes a lot less than rubber
11-28-2003, 10:56 AM
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Not 100% sure, but I think a spherical in that location would cause some binding. Steve?
-Jason Saini
www.over6racing.com
(accidentally posted under Juliann's account... doh)
-Jason Saini
www.over6racing.com
(accidentally posted under Juliann's account... doh)
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11-28-2003, 11:12 AM
#9
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Thread Starter
I just looked at my old LCA's, and you probably could get away with a spherical there, if you left the front bushing as rubber. The pivot axis of the front bushing does not intersect this rear bushing on center, so the front bushing wants to make the rear bushing's center swing thru a small arc, not just pivot about the center.
If you left the front bushing in rubber, it would probably give enough so as not to bind very much...but that is just speculation on my part. That front bushing is STIFF!
I think a bigger deal might be the change in corner entry dynamics. I think one of the reasons the S2000 turns in so well may be this bushing. Under braking, the front goes considerably toward toe out, and thus really wants to turn in. In return, you don't have to deal with corner exit toe out (which, I'm told, can cause push) or with excessive straight line scrubbing from lots of static toe out.
Steve
If you left the front bushing in rubber, it would probably give enough so as not to bind very much...but that is just speculation on my part. That front bushing is STIFF!
I think a bigger deal might be the change in corner entry dynamics. I think one of the reasons the S2000 turns in so well may be this bushing. Under braking, the front goes considerably toward toe out, and thus really wants to turn in. In return, you don't have to deal with corner exit toe out (which, I'm told, can cause push) or with excessive straight line scrubbing from lots of static toe out.
Steve
11-28-2003, 11:16 AM
#10
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Thread Starter
Krazik's post just turned on a lightbulb 
. I was wrong in my previous post.
With a monoball in the front location, the pivot axis doesn't have to follow the axis of the adjuster bolt. So, the LCA pivot axis will be along a line drawn between the centers of the two spherical joints. I still think it could have a significant impact on the car's dynamics, though.
Steve
. I was wrong in my previous post.With a monoball in the front location, the pivot axis doesn't have to follow the axis of the adjuster bolt. So, the LCA pivot axis will be along a line drawn between the centers of the two spherical joints. I still think it could have a significant impact on the car's dynamics, though.
Steve
