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65 Posts
Discussion Starter · #1 ·
Hey guys!

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today I modified my upper control arms. i did NOT shorten them in order to get more camber, i wanted more CASTER.
I am pretty happy with the angle i got with my steel knuckles i made before:

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BUT, with only 5 degrees of caster the steering wheel just wont return to center properly.

I did NOT want to buy adjustable caster arms, because:
-they move your wheel forward
-the IS's lower control arm simply is not designed for it. you have a RIGID connection bewteen the LCA and the caster arm.
simply making the caster arm longer puts a lot of stress to the caster arm and LCA bushings as you are forcing the pivot points away from each other.

this is why i wanted to modify my upper control arms.
what you need is a welder and some scrap metal.

start with spot welding your pivot points to a tube. they have to stay at the exact same point relative to eachother.

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now you have to find a piece of scrap metal which is laying in your backyard for way too long. you have to weld it to the tube so that you have a reference point where the ball joint originally was.
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mark where the center of your ball joint is.
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now you can cut off the UCA from the pivot points.
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now it depends on how much caster you want. i have about 5 degrees and want to have 9. i did the math and my ball joint has to move 25mm backwards to achieve my goal.
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now we need to shorten the rear arm, otherwise our ball joint would go outwards by 10mm:
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add a piece of tube to the front arm. in my case in order to move the ball joint 25mm back, i had to:
-shorten rear arm by 10mm
-add 20mm tube to front arm
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see next post.

65 Posts
Discussion Starter · #2 ·
now get your old ball joint out when youre already here.
clean everything for a re-paint. dont get embarrassed by your friends.
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paint and install new ball joint
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now take that massaging hammer with you and give your lex a good time:
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after massaging dont forget to put your protection on ;)

youre done! you have gained some caster with 0$ paid, assuming you have a scrapyard behind your house and a welder in your garage.
and most important, your wheel stays where it is and no stress on the lower bushings!

whole job took me about 4-5 hours.

enjoy 馃嵒

935 Posts
This is what I had a buddy of mine do for extra camber on my IS300. He only cut off 10mm and it's been a while but he might have added castor as well. I had a spare set of UCA's from a junkyard car that appeared be true so I modified them. I then added new balljoints and Superpro bushings.
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