NAXJA Forums -::- North American XJ Association  

Go Back   NAXJA Forums -::- North American XJ Association > NAXJA Unibody Jeep Technical Forums > Jeep Cherokee XJ (1984 - 2001) > Modified Tech Discussion
HOME Member FAQ Sponsor Info Rules Bylaws E-Mail

Modified Tech Discussion Forum for Tech related discussion for Modified XJ's and MJ's.

Reply
 
Thread Tools Display Modes
  #1  
Old October 19th, 2017, 20:51
jeeperguy21's Avatar
jeeperguy21 jeeperguy21 is offline
NAXJA Forum User
 
Join Date: Jun 2007
Location: Syracuse, UT
Posts: 784
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?
Reply With Quote
  #2  
Old October 20th, 2017, 07:38
Tim_MN's Avatar
Tim_MN Tim_MN is offline
Freakish Hand Strength
 
Join Date: Mar 2003
Location: Minneapolis, MN
Posts: 6,161
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.
__________________
.
.

Quote:
Originally Posted by bimmerjeeper

I'm starting to realize people on the Jeep forums are highly expert mechanics .....

Last edited by Tim_MN; October 20th, 2017 at 08:10.
Reply With Quote
  #3  
Old February 1st, 2018, 13:16
burntkat burntkat is offline
NAXJA Member #1145
 
Join Date: Apr 2003
Location: Charleston, SC
Posts: 1,163
Re: Knuckle rotation questions - caster change

Quote:
Originally Posted by Tim_MN View Post
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.
Concur, and also, is he measuring with the axle still in a vehicle, on a surface that is not level? Granted, all level measurements are done to the local gravity well, but if the axle is evenly mildly twisted up, this can give you junk data. I'd at least take the measurements on a hard flat surface (driveway is close enough for government work, unless it's uphill like mine). Even then, you're looking at a ballpark measurement. I wouldn't sweat accurate measurements till you have it out of the vehicle and on stands. What you want to measure before removing it, is how you need to adjust your pinion. Assuming you're running a DC front shaft (DC at the T-case), you want to point the pinion right at it. Figure out what the pinion needs to do (degrees up/down,and how many from level) to get there, and write it down.

Rip the axle out. But it on stands. Level itside/side, and fore/aft. Tear it down to parade rest, and take a grinder to those C welds. When you have a fine line visible where weld was, take a steel hammer to them till you break them loose. Now set your pinion angle where you want it. Check, check, triplecheck, and check again that the axle is still level side/side, fore/aft. Figure a way to hold it in place (I think a chain vise would work here, this is what I'm trying to figure out without building special fixturing I don't have room for). Now give the C's a few lovetaps till they are fully engaged with the tube, and around 6 degrees positive caster (ie, top inclined back toward the pinion). Tack each lightly in place , and recheck your work. Tack heavily, and check again. When happy, burn them in.

While this is probably pedantic and overly cautious, I'll be burning mine in in sections about 1" long at a time, then going to the other side to weld on it, then allowing them to cool before continuing. This will take quite some time. DO NOT *ever* quench the weld to cool it off so you can work faster.

This will take hours, of course. I have time to make sure I end up with a good product. I am not doing this for a job, I don't have a supervisor breathing down my back to hurry.

Definitely a shadetree approach to the problem, but it's worked for me so far (see below.. . It took me about 3 hours to do the welds on my highsteer tierod and draglink. Knock wood, but I've had no problems.
__________________
-89 S-10: SAS, D44s front/rear. 5.7L V8. 700R4 with 4L60E upgrades. Built in my driveway.
-90 XJ 4.0, AW4, 231J: Clayton's longarms, RE 5.5" coils, hybrid 6" leaf pack, 33/12.50/15" MTs, Rancho 99012s and 99624s, Tera HD SYE, custom sliders, BW flares. Rehabbing with D44s, RE spring packs, RE 4.5" coils, and ACOS.
-94 ZJ: Budget boost, 31s. The wife's DD.
-97 XJ: Son's DD. 4" lift, ACOS, 4" spring pack, Upcountry coils, 31s
Reply With Quote
  #4  
Old October 20th, 2017, 07:56
jeeperguy21's Avatar
jeeperguy21 jeeperguy21 is offline
NAXJA Forum User
 
Join Date: Jun 2007
Location: Syracuse, UT
Posts: 784
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.
Reply With Quote
  #5  
Old October 20th, 2017, 09:05
Tim_MN's Avatar
Tim_MN Tim_MN is offline
Freakish Hand Strength
 
Join Date: Mar 2003
Location: Minneapolis, MN
Posts: 6,161
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.
__________________
.
.

Quote:
Originally Posted by bimmerjeeper

I'm starting to realize people on the Jeep forums are highly expert mechanics .....
Reply With Quote
  #6  
Old October 20th, 2017, 09:12
jeeperguy21's Avatar
jeeperguy21 jeeperguy21 is offline
NAXJA Forum User
 
Join Date: Jun 2007
Location: Syracuse, UT
Posts: 784
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.
Reply With Quote
  #7  
Old February 1st, 2018, 13:18
burntkat burntkat is offline
NAXJA Member #1145
 
Join Date: Apr 2003
Location: Charleston, SC
Posts: 1,163
Re: Knuckle rotation questions - caster change

Quote:
Originally Posted by jeeperguy21 View Post
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.
I would reconsider going to 8 degrees. 6 should be plenty. It sounds like very little difference, but it's huge.
__________________
-89 S-10: SAS, D44s front/rear. 5.7L V8. 700R4 with 4L60E upgrades. Built in my driveway.
-90 XJ 4.0, AW4, 231J: Clayton's longarms, RE 5.5" coils, hybrid 6" leaf pack, 33/12.50/15" MTs, Rancho 99012s and 99624s, Tera HD SYE, custom sliders, BW flares. Rehabbing with D44s, RE spring packs, RE 4.5" coils, and ACOS.
-94 ZJ: Budget boost, 31s. The wife's DD.
-97 XJ: Son's DD. 4" lift, ACOS, 4" spring pack, Upcountry coils, 31s

Last edited by burntkat; February 1st, 2018 at 13:24.
Reply With Quote
  #8  
Old November 22nd, 2017, 08:46
jeeperguy21's Avatar
jeeperguy21 jeeperguy21 is offline
NAXJA Forum User
 
Join Date: Jun 2007
Location: Syracuse, UT
Posts: 784
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
Reply With Quote
  #9  
Old December 4th, 2017, 14:27
XJEEPER's Avatar
XJEEPER XJEEPER is offline
NAXJA Member # 13
 
Join Date: Aug 2002
Location: Wasatch Range
Posts: 8,977
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
__________________
Speak the Truth-Question with Boldness-Speak without fear.
Reply With Quote
  #10  
Old December 4th, 2017, 15:15
jeeperguy21's Avatar
jeeperguy21 jeeperguy21 is offline
NAXJA Forum User
 
Join Date: Jun 2007
Location: Syracuse, UT
Posts: 784
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.
Reply With Quote
  #11  
Old December 5th, 2017, 09:16
XJEEPER's Avatar
XJEEPER XJEEPER is offline
NAXJA Member # 13
 
Join Date: Aug 2002
Location: Wasatch Range
Posts: 8,977
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.
__________________
Speak the Truth-Question with Boldness-Speak without fear.

Last edited by XJEEPER; December 5th, 2017 at 09:31.
Reply With Quote
  #12  
Old December 5th, 2017, 09:42
jeeperguy21's Avatar
jeeperguy21 jeeperguy21 is offline
NAXJA Forum User
 
Join Date: Jun 2007
Location: Syracuse, UT
Posts: 784
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.
Reply With Quote
  #13  
Old January 29th, 2018, 15:02
jeeperguy21's Avatar
jeeperguy21 jeeperguy21 is offline
NAXJA Forum User
 
Join Date: Jun 2007
Location: Syracuse, UT
Posts: 784
Re: Knuckle rotation questions - caster change

I am pleased to report that I was able to get my axle C's to rotate after grinding further into the C's. I've got them rotated to 8 degrees, which will be a night and day difference compared to them being a 1 degree previously.

I need to replace my ball joints as at least one of them is confirmed to be bad on the passenger side. It seemed to fail while I was trying to remove the knuckle. You can see a lovely clip of what this failure looks like here:
https://www.youtube.com/watch?v=Q7uAYoaAYtU

I need the help of someone to weld these puppies back into place. I have 3 neighbors that weld, but I don't fully know their level of competency. I have considered hiring someone on the local online classifieds, but haven't pulled the trigger on that yet. Any local volunteers? I will pay handsomely with a free meal, internet points, or cash. I have a 240V outlet in my garage. Needing someone that is mobile and can come to me.

I took two vastly different approaches to the driver and passenger side. I did the driver side first and thought it would be best to completely grind off the original weld. This means that this side will need to be built back up to the thickness of the original weld: https://www.dropbox.com/s/7tcalcup5u...49.46.jpg?dl=0

I wised up after the first side and used only a cutoff wheel and sawzall on the passenger side which left most of the original weld in place, but I don't know if the space is wide enough to get a good weld in place: https://www.dropbox.com/s/oycj9kakdc...48.56.jpg?dl=0

I want to make this as easy as possible for whoever I end up getting to do this. Thoughts?

Also, if anyone has a recent opinion of ball joints, feel free to share. It seems like the common theme I'm finding is that Moog joints aren't what they used to be, Spicer is a safe bet, and other brands are hit and miss.
Reply With Quote
  #14  
Old December 4th, 2017, 21:31
donthelegend donthelegend is offline
NAXJA Member
 
Join Date: Apr 2010
Location: St. Louis, MO
Posts: 379
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 21:38.
Reply With Quote
  #15  
Old January 31st, 2018, 15:48
jeeperguy21's Avatar
jeeperguy21 jeeperguy21 is offline
NAXJA Forum User
 
Join Date: Jun 2007
Location: Syracuse, UT
Posts: 784
Re: Knuckle rotation questions - caster change

Bump:

TLDR: Looking for a local to weld my rotated axle C's into place.

Also wondering what the latest opinions are on ball joints. Need to replace my Moog joints, but don't know if Moog is still a solid option.
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Knuckle rotation contemplation XJEEPER Advanced Fabrication and Engineering 87 September 20th, 2011 10:26
will caster change effect camber too? Shorty Modified Tech Discussion 10 November 24th, 2008 16:02
tube rotation/caster adjustment? 1998xj1985 Modified Tech Discussion 4 October 19th, 2006 13:50
Check my figures on knuckle rotation please 87xjco Modified Tech Discussion 10 July 18th, 2006 15:30
D44 Knuckle Rotation Question slvr98svt Modified Tech Discussion 7 August 25th, 2005 15:03


All times are GMT -7. The time now is 07:13.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
NAXJA and NAXJA logo's Copyright NAXJA. All content/images Copyright NAXJA 1999-2014