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  #1  
Old October 19th, 2017, 21:51
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jeeperguy21 jeeperguy21 is offline
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Knuckle rotation questions - caster change

I am about to dive into the process of rotating the axle C's to get a better caster angle. Prior to making any adjustments, I measured the current angle on both the driver and passenger sides and am getting different measurements. The passenger side shows 1.1 degrees and the driver side shows 2.3 degrees, shown in the links below:

https://www.dropbox.com/s/0ldsdayjsd...27.50.jpg?dl=0

https://www.dropbox.com/s/3cyuq4oxwp...27.04.jpg?dl=0

Couple of questions:
1) Am I measuring this correctly?
2) Should I try adjusting the control arms to have the caster match on both sides before I start grinding away?
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  #2  
Old October 20th, 2017, 08:38
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Re: Knuckle rotation questions - caster change

Are you measuring from a raw casting surface, or from a machined surface ? I would be rough measuring caster from the top of the ball joint, or better yet, with the outer C and ball joint removed, measure from the flat machined surface at the ball joint opening. Some variation in caster is certainly possible.

I would be setting the caster angle in only relation to the axle housing, and not in relation to the control arms or the Jeep.

If you are using short control arms, minor caster adjustments can be made with caster shims on the frame side of the control arm.
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Last edited by Tim_MN; October 20th, 2017 at 09:10.
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Old October 20th, 2017, 08:56
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Re: Knuckle rotation questions - caster change

I was measuring from the surface right next to the top of the lower ball joint. As I was trying to figure out the best place to measure the caster, I also got a measurement from on top of the top ball joint, which had the passenger caster at 1.8 degrees. I don't recall what it was on the driver side as I didn't snap a pic. Here's a pic of the passenger side:

https://www.dropbox.com/s/cpodda8913...23.49.jpg?dl=0

Since some variation in caster is possible, should I make it the same on both sides before I adjust it, or just proceed and make them the same afterwards? I have long control arms that are easily adjustable. I would just need to decide if I should make the top shorter or the bottom longer on one side during the adjustment.
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Old October 20th, 2017, 10:05
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Re: Knuckle rotation questions - caster change

Since you are going to change the caster, the current measured caster numbers, nor any side to side variance, do not matter, they are only used as a reference. Measure, or assume that the frame side mounts are equal distance from the axle, then make sure the adjustable control arms are close to each other in length, and get to work.

Rotate the C's in relation to the axle housing.
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Old October 20th, 2017, 10:12
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Re: Knuckle rotation questions - caster change

Sounds good. I plan on rotating both sides so that they are at 8 degrees. I'll make sure the arms are the same length on both sides and then go for it.

Not looking forward to this project, but I'm looking forward to the end result.
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Old November 22nd, 2017, 09:46
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Re: Knuckle rotation questions - caster change

I started grinding away on the welds holding the axle C's on the driver's side. I must not have enough of the weld ground away because I can't get it to rotate with a BFH. I don't want to grind too much into the axle tube, so I'm looking for a second opinion on where I need to focus my grinding efforts. Here are some pics:

https://www.dropbox.com/s/3ig0sl5qz4...56.40.jpg?dl=0

https://www.dropbox.com/s/ue6egaz7ys...53.34.jpg?dl=0

https://www.dropbox.com/s/b0426lvs50...53.47.jpg?dl=0

https://www.dropbox.com/s/xae8xyomoe...55.39.jpg?dl=0

https://www.dropbox.com/s/qoxy4hhzys...55.55.jpg?dl=0
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Old December 4th, 2017, 15:27
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Re: Knuckle rotation questions - caster change

I PMed you the link to my knuckle rotation thread, but I'll share it here as well. Too bad Photobucket killed my picture links, but there are good descriptions of each step, which should help.

http://www.naxja.org/forum/showthrea...ation &page=4
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Old December 4th, 2017, 16:15
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Re: Knuckle rotation questions - caster change

Quote:
Originally Posted by XJEEPER View Post
I PMed you the link to my knuckle rotation thread, but I'll share it here as well. Too bad Photobucket killed my picture links, but there are good descriptions of each step, which should help.

http://www.naxja.org/forum/showthrea...ation &page=4
I read the thread in great detail prior to reaching out to you. I was able to see the pics using a Chrome extension that makes them visible. I'm hoping for some advice one where I currently stand. In my opinion, I think I've ground sufficiently, but the C's won't budge. I'm putting quite the mark on them as I've pounded them with a sledge.

I'm wondering if you can see anything obvious in the pics to point me in the right direction. Is it more grinding into the axle tube that I need to do, try to focus my efforts onto the C's themselves, or something else? The last thing I want to do is to grind a hole into the tube by attacking this the wrong way.
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Old December 4th, 2017, 22:31
donthelegend donthelegend is offline
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Re: Knuckle rotation questions - caster change

Did you cut fairly deeply into the inner C or stay farther out (so you were grinding more of the weld rather than the metal of the inner C)? I see a couple spots that look kinda like the end of the weld but it's hard to tell. The best way I can describe it is that it looks like a small "tear" at the transition point. I'm going to try to mark up a couple of your pics and I'll post them in a minute.

Edit:



Last edited by donthelegend; December 4th, 2017 at 22:38.
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Old December 5th, 2017, 10:16
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Re: Knuckle rotation questions - caster change

Quote:
Originally Posted by jeeperguy21 View Post
I read the thread in great detail prior to reaching out to you. I was able to see the pics using a Chrome extension that makes them visible. I'm hoping for some advice one where I currently stand. In my opinion, I think I've ground sufficiently, but the C's won't budge. I'm putting quite the mark on them as I've pounded them with a sledge.

I'm wondering if you can see anything obvious in the pics to point me in the right direction. Is it more grinding into the axle tube that I need to do, try to focus my efforts onto the C's themselves, or something else? The last thing I want to do is to grind a hole into the tube by attacking this the wrong way.
It's difficult to tell from your images, if you have removed enough of the weld/knuckle to allow the knuckle to rotate freely on the tube, but suffice to say that if the knuckle is not rotating with the application of force from your hammer, then you need to remove more material.

It appears to me from the image 18.55.39, that you haven't sliced into the lower-rear section of the knuckle enough to cut through the weld.

I recall shaving about 1/8"+ from the inner knuckle surface, in order to get behind the factory weld. This required several cutoff discs and a right-angle die grinder to accomplish.

http://i173.photobucket.com/albums/w...I/100_2964.jpg

A small section of weld will prevent the entire knuckle from rotating.
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Last edited by XJEEPER; December 5th, 2017 at 10:31.
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Old December 5th, 2017, 10:42
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Re: Knuckle rotation questions - caster change

Thanks for looking at the pics, guys. I now think that I attacked the weld much more so than the inner C. I don't believe I really got into the inner C much, which is likely what is causing my inability to free it from the axle tube.

Next time I have a chance to grind, I will focus most, if not all of my efforts on shaving down the inner C to try and free it up. I'll let you know what the outcome is.
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