Rock crawling CJ5 Suspension help/Advice

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  • rang-a-stang
    Administrator
    • Oct 31, 2016
    • 5505

    Rock crawling CJ5 Suspension help/Advice

    My brother has a pretty darn righteous CJ5 he bought a couple years ago. It is a REALLY nicely built rock crawling rig he bought used. Off road, it is AMAZING. On the road it is really sketchy. To the point that his wife won't ride in it and doesn't like the kids riding in it (on the street). We are trying to think of some ways to improve the street driving characteristics.

    First some details:
    73 Cj5, 350, TH350, NP205, fully boxed frame, GM 10 bolt front with Detroit locker, Ford 9 inch with Detroit locker,
    Front, is kind of a 3 point I guess; it has what looks like Ford tubular trailing arms, coil springs, Bilsteins, and a track bar but I do not see an upper control arm. Steering is a high steer/crossover setup with a Saginaw steering box.
    Rear is a triangulated 4 point with brand new Bilsteins and a coil springs.
    Wheel base is about 7" longer than stock CJ5. Almost new 35" A/T Tires, just had an alignment. I felt very little slop (but there was some) in the
    steering box. None of the bushings or tie rods had slop that I could see.

    What makes it sketchy?
    1) The center of gravity is pretty high and there are no sway bars. Every change is momentum the whole truck moves. Give it gas and it wants to turn left a little. Let go of the gas and it wants to wander into the lane next to you.
    2) steering is SUPER soft and it has a tiny steering wheel. When the truck does sway into another lane and you counter with some steering feedback, the body sways and wants to add more motion and it wants to over correct.

    What have we done so far?
    A) He wants to put a sway bar(s) on but there is no easy place to put it/them. We spent a good 30 mins trying to think of a place to mount the way bar and the end links. It could be done but he is not a fabricator and would prefer not dump $500 on having some mounts fabricated if it isn't really gonna make a big difference.
    B) His front coil spring mounts bolt on to the frame and are adjustable. We tried lowering the front end as much as we mechanically could (was about 4" at the front winch) but then the crossover link (at the pitman arm) was only about 1.5" above the drag link and would have contacted anytime the suspension compressed more than 1.5". He could move the drag link under the knuckle to gain steering clearance but then he loses ground clearance. Again, he would be willing to do that if it would make a pretty drastic change in handling characteristics but neither of us was confident it would so we put it back.

    Pics:









    So, any ideas that could help? Stiffer springs? Add a third mounting point to the front axle? Sway bars/Anti-rock? a bigger steering wheel?
    Last edited by rang-a-stang; 03-01-2021, 09:49 PM.
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  • SJTD
    304 AMC
    • Apr 26, 2012
    • 1953

    #2
    Hard to see from the pics but what's the relationship between the panhard bar and the drag link? Ideally they would be parallel to the ground but they should always be parallel to each other.

    If at unequal angles, when the suspension compresses the axle moves sideways but the drag link doesn't, being attached to the box. This causes a steering input. If they're parallel the wheels stay pointed where they were.

    The closer to parallel to the ground they are the less the axle moves sideways on bumps which is always better.

    Making the front a four link won't cure it unless the drop link is made parallel to ground. With a four link the axle moves straight up but the drop link will cause an input if it's at an angle. The steeper the angle the worse the pump steer will be with any setup. This is why leaf spring fronts will have bump steer without a dropped pitman arm.

    Sway bar always helps but it's more for body roll.

    Has correct caster for less tendency to wander?

    That was a four wheel alignment? Everything pointed in the right direction is always good.
    Last edited by SJTD; 03-02-2021, 07:29 AM.
    Sic friatur crustulum

    '84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

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    • rocklaurence
      Moderator

      Moderator
      • Jan 14, 2009
      • 1841

      #3
      In my '80 CJ5 it had 57" leaf springs and sway bars front and rear. It was low to the ground with 38" Boggers and was the best all-a-round driver of any CJ Ive had. Make sure the Caster is approx' 4 degrees and add the sway bars.
      Note: I didnt see any way to adjust the Caster on that front suspension.

      Comment

      • rang-a-stang
        Administrator
        • Oct 31, 2016
        • 5505

        #4
        Originally posted by SJTD
        Hard to see from the pics but what's the relationship between the panhard bar and the drag link? Ideally they would be parallel to the ground but they should always be parallel to each other.

        If at unequal angles, when the suspension compresses the axle moves sideways but the drag link doesn't, being attached to the box. This causes a steering input. If they're parallel the wheels stay pointed where they were.

        The closer to parallel to the ground they are the less the axle moves sideways on bumps which is always better.

        Making the front a four link won't cure it unless the drop link is made parallel to ground. With a four link the axle moves straight up but the drop link will cause an input if it's at an angle. The steeper the angle the worse the pump steer will be with any setup. This is why leaf spring fronts will have bump steer without a dropped pitman arm.

        Sway bar always helps but it's more for body roll.

        Has correct caster for less tendency to wander?

        That was a four wheel alignment? Everything pointed in the right direction is always good.
        I believe it was a 4 wheel alignment. Draglink and panhard are parallel to each other but not the ground. You may be on to something there. hmmm....
        Originally posted by rocklaurence
        In my '80 CJ5 it had 57" leaf springs and sway bars front and rear. It was low to the ground with 38" Boggers and was the best all-a-round driver of any CJ Ive had. Make sure the Caster is approx' 4 degrees and add the sway bars.
        Note: I didnt see any way to adjust the Caster on that front suspension.
        I do not believe there is a way to adjust caster. I will ask my brother if he got a read out of the alignment and to get a picture of the panhard/drag link.
        Chuck McTruck 71 J4000
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        (8.1L swap questions - PerformanceTrucks.net Forums​)
        79 Cherokee Chief (SOLD, goodbye old buddy)
        (Cherokee Build Thread)
        11 Nissan Pathfinder Silver Edition 4x4
        09 Mazdaspeed3 Grand Touring
        00 Baby Cherokee

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        • rang-a-stang
          Administrator
          • Oct 31, 2016
          • 5505

          #5
          So when trying to figure out the angle of the track bar, is it the angle that is created by drawing a straight line between the 2 mounting points or the line that is down the middle of the longest, straightest part of the track bar?

          The reason I ask is if you look at his track bar, the upper mount is significantly higher and the straight line between the 2 mounting points would make a very steep angle, but the track bar is built where the majority of the bar is parallel or almost parallel to the ground.

          Better pictures of front suspension/steering.



          Chuck McTruck 71 J4000
          (Chuck McTruck Build Thread)
          (8.1L swap questions - PerformanceTrucks.net Forums​)
          79 Cherokee Chief (SOLD, goodbye old buddy)
          (Cherokee Build Thread)
          11 Nissan Pathfinder Silver Edition 4x4
          09 Mazdaspeed3 Grand Touring
          00 Baby Cherokee

          Comment

          • SJTD
            304 AMC
            • Apr 26, 2012
            • 1953

            #6
            Shape of the bar doesn't matter other than if it were curved a LOT allowing flex. I don't think it's a problem.

            Yea it's the point to point lines that should be parallel and again, parallel to the ground. The panhard does drop more the than the drag and it's shorter. Maybe looks worse in person? Lotta work to fix and might not cure the problem.

            I assume you've been looking at the CJ forums.
            Sic friatur crustulum

            '84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

            Comment


            • #7
              Not a steering geometry guru in any way, but the set-up for anchoring the axle end of the track bar frankly scares the hell out of me. Suspension and steering is no place to cobble stuff together.
              I don't blame the spouse for not getting in it. Way too many issues to be safe for either the owners or others on the road.

              I'd look for a long arm front kit with adjustable links to be able to set a decent caster. Might cost a bit, but at least it's engineered for the vehicle and safety. Other options might be the set-up from an XJ or TJ.
              Can't tell if the track bar is adjustable or not, doesn't look like it. As you raise the suspension with lift, you're pulling the axle to the left, putting a side load in the springs, links, and mounts. Going to want to dog track and be susustible to wander and take off at the slightest provocation.
              Last edited by goldhammer; 03-05-2021, 10:16 PM.
              Art
              ASE Master Collision Tech
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              • rocklaurence
                Moderator

                Moderator
                • Jan 14, 2009
                • 1841

                #8
                The Bar and Drag link are parallel but are different lengths. Meaning, that you will induce Bump Steer. However, I think the Sway is the biggest concern. IMO, adding sway bars will provide the biggest change.

                Comment

                • SJTD
                  304 AMC
                  • Apr 26, 2012
                  • 1953

                  #9
                  Take another look. The panhard takes a nice curve upward right about at the steering box to its frame mount.
                  Sic friatur crustulum

                  '84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

                  Comment

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