Rotating axle C's

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    Rotating axle C's

    Hey guys. I'm a long time lurker on JKO, but like many of you, I gave up on that site.

    I'm in need of some advise about adding some caster to a factory Rubicon axle. I know many people would say to just buy a new housing, but the $2500 just isn't in the budget. I'm also not a fan of offset ball joints. My two options appear to be rotating the axle C's or rotating the center section. I have gussets welded to the C's, but I can cut those out easily.

    I'm thinking that rotating the center section would be easier and would keep all the brackets except the passenger side upper mount in line. I would just move that one bracket to keep it in line with the fixed driver side mount. My main concerns are as follows:

    Would the change in upper control arm length in relation to the lowers really affect the suspension geometry, or are we talking about a minuscule amount?
    After drilling/grinding out the plug welds, do you think a bottle jack would be enough to rotate the center section on the tubes when they are mounted to a fixture table? I figure I would just use a bottle jack and push up on the pinion.

    Thanks,
    Jim

    #2
    I've always wondered if this could be a lazier way to cut and turn.
    Instead of trying to grind out the weld on the C or messing with the tube at the center section, you just chop the axle tube behind the C, sleeve the tube, then rotate the chopped C and burn on.
    Last edited by snout; 06-10-2020, 04:20 PM.

    Comment


      #3
      I've thought about that too, but I'd prefer not to cut the tube. I know people do this, and buying a set of inner sleeves can make this easier to do, but I just feel there may still be issues keeping things as aligned as I'd like without a lot of extra work. And the coil bucket makes for tight quarters on the driver side. I'm sure it's strong enough, I'd just rather try rotating the actual C's or rotate the center section.

      Thanks for the input Snout!

      Comment


        #4
        I did my stock D44 Rubicon housing and it was fairly simple.

        I used a thin 6" cutoff wheel and sliced the weld right at the inner C all the way around until I got down to the tube. Heated up the C a little and used a big hammer to tap it backwards (positive caster) until I got it where I wanted it. I double, tripple and quadruple checked my caster & camber, then made sure the slice was still the thickness of the cutoff wheel all the way around, ground down the old weld in 4 spots and tacked the C in place. Then I ground down all the rest of the old weld and finish welded the C.

        Here is a finished picture with the Artec truss and Inner C stiffeners welded on.
        Click image for larger version  Name:	20190708_144209.jpg Views:	0 Size:	417.2 KB ID:	35496

        Comment


          #5
          1 more thing...... You need to either carefully cut off the spring pads so you car reuse them, or purchase new ones from your favorite vendor. They need to come off to get a grinder in there.

          Comment


            #6
            If you are adjusting for caster turning the pumpkin won't effect caster. it will change your drive line angles. unless the pumpkin is attached to frame and tubes are not. Am not a jeep guy. you need to turn the C's do you know what the caster is atm? prob only need +2 deg more to make it nice.
            Last edited by Wes Harden; 06-10-2020, 07:51 PM.

            Comment


              #7
              Originally posted by SLOWPOKE693 View Post
              I did my stock D44 Rubicon housing and it was fairly simple.

              I used a thin 6" cutoff wheel and sliced the weld right at the inner C all the way around until I got down to the tube. Heated up the C a little and used a big hammer to tap it backwards (positive caster) until I got it where I wanted it. I double, tripple and quadruple checked my caster & camber, then made sure the slice was still the thickness of the cutoff wheel all the way around, ground down the old weld in 4 spots and tacked the C in place. Then I ground down all the rest of the old weld and finish welded the C.

              Here is a finished picture with the Artec truss and Inner C stiffeners welded on.
              Click image for larger version Name:	20190708_144209.jpg Views:	0 Size:	417.2 KB ID:	35496
              Thanks for the reply!

              The reason I'm leaning towards turning the center section is to avoid buying spring perches for a axle I'm not planning on keeping more than another year or two. I'm not even going to bother trussing it. I've been wheeling this Jeep since new in 2014 and so far I've managed not to bend anything. I'm eventually going one tons but I just want to add more caster to get a better ride and fix driveline angles.

              How far off do you think the spring perches would be if I left them alone? So far I'm seeing about 3/16" as the total rotation needed to get 10 degrees of separation. I can't imagine that would be too horrible or noticeable on the springs.


              Comment


                #8
                Originally posted by Wes Harden View Post
                If you are adjusting for caster turning the pumpkin won't effect caster. it will change your drive line angles. unless the pumpkin is attached to frame and tubes are not. Am not a jeep guy. you need to turn the C's do you know what the caster is atm? prob only need +2 deg more to make it nice.
                Wes,

                My thinking was that if I rotate the center section up so there is 10 degrees of separation between the pinion and axle C's, I can add more caster by adjusting the upper control arms and it would keep the pinion pointed towards the t-case. This would keep all the mounts except the two uppers in correct position. One is fixed and the other I would move to align it with the fixed one. I'm just not sure how easy it will be to rotate the center section on the tubes. It seems easier to do than cutting the axle C's, but I'm not seeing anyone do it with a JK axle.

                I may end up just cutting the axle C's just to be on the safe side. I have a couple of weeks before I start this project to decide.

                Comment


                  #9
                  Few questions......

                  -How much lift are you running?
                  -What size tires?
                  -If you can move the passenger mount, why cant you move spring pads?
                  -Why do you think you need to do this if it's been ok since 2014 and your going to tons in a year?

                  In the "move the pumpkin up" scenario, you would be moving all the axle brackets backwards to gain caster after you move the pumpkin. I honestly don't understand the logic behind this.

                  Me being me answer....... If buying or building a new set of spring pads breaks the bank, or is beyond your skill set, let's face it, tons ain't happening.


                  Just build it right.

                  Comment


                    #10
                    Originally posted by SLOWPOKE693 View Post
                    Few questions......

                    -How much lift are you running?
                    -What size tires?
                    -If you can move the passenger mount, why cant you move spring pads?
                    -Why do you think you need to do this if it's been ok since 2014 and your going to tons in a year?

                    In the "move the pumpkin up" scenario, you would be moving all the axle brackets backwards to gain caster after you move the pumpkin. I honestly don't understand the logic behind this.

                    Me being me answer....... If buying or building a new set of spring pads breaks the bank, or is beyond your skill set, let's face it, tons ain't happening.


                    Just build it right.
                    3.5" lift, but it's light so more like 4 inches in the front.

                    35's for now.

                    I can move the pads, but its a lot more work than moving an upper control arm mount sitting in the middle of a long tube.

                    The balance between caster and driveline angles is getting old. The Jeep drives ok, but not nearly as good as it would if I added even 1 degree of caster. I know this because I have tried.

                    I currently get vibrations around 75mph. That in itself isn't bad, but it sucks going 70ish for 16 hours when the speed limit can be up to 75. It's not a crazy vibration, but it's always on my mind while traveling at freeway speeds. The vibrations might be due to the Adams driveshaft being made 1 inch too long so it rides off the Glidecoat. That's a whole other story though. I plan on shortening the shaft after I get the driveline angle fixed.

                    In the rotating the axle C scenario, I would be moving the upper axle brackets forward when rotating the pinion up. Either way, the brackets have to move. The difference is the brackets moving 4+ degrees forwards vs 1 or 2 degrees backwards. And moving one bracket that's easy to get to is easier than moving 2 spring perches that are close to the axle C's.

                    The money isn't the problem for spring perches. It's just money wasted if rotating the center section is feasible. And there's a huge difference in buying spring perches vs tons.

                    I understand that this is a web forum and I'm new to everyone, but the fabrication part isn't a concern. To me, it just looks more logical to drill out 4 plug welds and push the pinion up. I guess I'm just looking for the negatives associated with that plan. I'm open to either option, but I want to know what I'm missing. Could it be the new suspension geometry associated with moving the upper mounts forwards in relation to the stationary lowers?

                    Thanks again Slowpoke.

                    Comment


                      #11
                      Key word in your above post is: Currently


                      So there was no problem before with your unrotated pumpkin, now you get a vibration at 75 and you think it's because you need to rotate the pinion up? More questions......

                      -Are you positive it's the front that is vibrating?
                      -Are ALL of your front suspension bushings/joints in good shape?
                      Track bar bushings good?
                      -Trackbar holes wallowed out?
                      -Jambnuts tight?
                      -Balljoints good?
                      -Unit bearings good?
                      Axle joints good?
                      -Driveshaft issue isnt a concern?
                      -You drive 16hrs often?


                      My wifes daily driver 16 JKUR has 3.5" springs, stock housings F&R with Artec goodies and the 2° extra caster mod I mentioned above and I have no vibration at 75-80 rolling around on 40's and beadlocks. Mind you, when I moved the C's it wasn't to correct pinion angle, it was to add caster for better tracking, so my pinion is still pointing in the stock location relative to the transfer case. I'm also running Adam's driveshafts F&R.
                      Last edited by SLOWPOKE693; 06-10-2020, 11:05 PM.

                      Comment


                        #12
                        Couple things stand out between rotating the C's or the pumpkin. C's are forged and easy to weld. Pumpkin is cast iron and a bit more tricky to weld to the tubes, and you are going to want to weld pumpkin/tubes after you rotate it. The plug welds in the pumpkin are not small, so once you've drilled them out and rotated the tubes, you're still going to have partially open through holes to fill.

                        Cut and turning the C's is your best bet.

                        Once you installed bigger tires and/or different backspace wheels you've changed your scrub radius and pretty much every other spec in the geometry. So, if you think about it, the factory alignment specs don't really apply to you anymore. It's no longer the vehicle they were intended for. JK's run as little caster as they can get away with to keep the soccer moms happy pulling into the best parking spots at Macy's. They want the least amount of effort to turn the wheels on a bone stock vehicle.

                        4* of caster is.......well.....not much. It's probably one of the reasons they're one wrong bump away from death wobble at any time. If you're going to all the trouble of cutting and welding, give yourself a good amount of caster to work with. There is nothing wrong with 8, 10, 12 degrees of caster. You would literally have to get up into the 20's before "too much" became an issue.

                        Caster gives you the return to center in your steering. When you turn, the outside tire gains negative camber and the inside tire gains positive camber, when you have more caster.

                        Edit: I honestly don't understand why more folks don't rotate their C's, rather than spending thousands to buy a housing that has rotated C's.
                        Last edited by gt1guy; 06-10-2020, 11:39 PM.
                        Kevin

                        Comment


                          #13
                          Slowpoke,

                          The problem has been there since I installed an Adams shaft. They told me to send it back and they'd send me another one. That one has the same Glidecoat problem. Like I said, it's not a huge deal and that is not the main reason I want to do this. Its not a crazy vibration, but the shaft has a lot of movement in it at the splines because they don't engage on the Glidecoat. If I disconnect the axle side and put the spline on the Glidecoat, I have almost no play. The driveshaft also doesn't seal well and allows a huge amount of water and mud in at the splines. After 3 trips, I have had to take the slip joint apart and clean it out. It gets full of mud and water and seizes. I spoke to Adams about this and they agreed that could be an issue. They offered to shorten my driveshaft for 80 dollars plus shipping each way. I didn't feel it was worth it when I can get it done locally for about the same price but without shipping. I rebuilt it a few weeks ago just to rule out bad joints. With the driveshaft in, it has the vibration. If I take it out, the vibration is gone. I'm confident the problem is the front driveshaft.

                          I didn't make the post to diagnose my driveline issue though. My primary reason for doing this is to make the Jeep drive better. However, if I add more caster, the vibration seems to get worse. I'm just tired of the compromises. This mod should help with both issues.

                          I'll cover your questions so we're all on the same page.

                          The vibration isn't there when the shaft is removed. Due to this, I remove it for long trips. I drive 16 hours 2-4 times a year, and do 6-10 hour trips at least another 4-5 times a year. I try to get out and do 2-3 hour trips a couple of times a month (not so much during winter). Those drives happen often enough for me to sit there and think a lot about the vibration.

                          All bushings are good and tight. The track bar isn't wallowed out and the jam nuts are tight. I put witness marks on them to make sure. They haven't moved in almost 60,000 miles unless I did it. Ball joints are good and replaced around 20,000 miles ago due to a small amount of play. Unit bearings are good. I check them and the balljoints every 3-4000 miles during tire rotation. Axle u joints were good when I replaced the balljoints. I'll probably replace them while the axle is out for this mod though. All zerks, including the double carden centering ball, get lubed up every tire rotation.

                          I know that many people have a similar set up and have no issues. I, however do. It's not huge and I wouldn't do this just to correct a small vibration. I'm primarily doing this for better handling. The driveline having a better angle is just a bonus.

                          Comment


                            #14
                            Originally posted by gt1guy View Post
                            Couple things stand out between rotating the C's or the pumpkin. C's are forged and easy to weld. Pumpkin is cast iron and a bit more tricky to weld to the tubes, and you are going to want to weld pumpkin/tubes after you rotate it. The plug welds in the pumpkin are not small, so once you've drilled them out and rotated the tubes, you're still going to have partially open through holes to fill.

                            Cut and turning the C's is your best bet.

                            Once you installed bigger tires and/or different backspace wheels you've changed your scrub radius and pretty much every other spec in the geometry. So, if you think about it, the factory alignment specs don't really apply to you anymore. It's no longer the vehicle they were intended for. JK's run as little caster as they can get away with to keep the soccer moms happy pulling into the best parking spots at Macy's. They want the least amount of effort to turn the wheels on a bone stock vehicle.

                            4* of caster is.......well.....not much. It's probably one of the reasons they're one wrong bump away from death wobble at any time. If you're going to all the trouble of cutting and welding, give yourself a good amount of caster to work with. There is nothing wrong with 8, 10, 12 degrees of caster. You would literally have to get up into the 20's before "too much" became an issue.

                            Caster gives you the return to center in your steering. When you turn, the outside tire gains negative camber and the inside tire gains positive camber, when you have more caster.

                            Edit: I honestly don't understand why more folks don't rotate their C's, rather than spending thousands to buy a housing that has rotated C's.

                            Thanks gt1guy.

                            I have followed your build since the first day you posted it on JKO. If I remember correctly, you went with 12 degrees of caster. Going more is definitely on my mind. I'm referencing 10 degrees because that is the standard for aftermarket axles and it's easy math when I talk about the changes.

                            I've never welded cast iron before, but I would be purchasing some Ni55 (or equivalent) to do this. Lincoln has some great tips for preheat, cool down and weld settings so I'm confident I'd be able to pull it off. It is, of course, still a huge concern. I googled this concept and it's definitely been done, but I only see examples of this done on leaf sprung vehicles. I'm mostly curious if the change in suspension geometry due to the new location of the upper arm mounts would be noticeable. I may have to get under there tomorrow and take some measurements to plug into a 4 link calculator. My gut tells me the new position wont matter, but once its done, its not going back.

                            Thanks again for the help guys.

                            Comment


                              #15
                              Yes, I set my axle up with 12* caster. I think it came out to 17*-18* separation. Main reason was more return to center to help out with the full hydro on the street. Even if I wasn't going full hydro, I probably would have still done it for the other benefits.

                              If you're confident in your welding, doing the tube turn wont be a problem. Just seems to me that the C's would be easier.

                              Do you have adjustable control arms?

                              Doing some quick math, turning the tubes even 5* is only .109" at the tube. Not sure how high the upper arm mount is, but I can't see it doing a whole lot of movement.
                              Kevin

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