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  1. #1
    Join Date
    Sep 2009
    Chico, CA

    Default How to build a three or four link suspension

    Next, it is time to build the brackets for the rod ends. First start with a piece of 1/4X6X8” steel.

    Measure up 1” from the bottom and 2 ½” from the left side. Mark that and then measure up 4” and to the right 4” and mark that. Then drill two 9/16” holes. Then take two 9/16” nuts and weld one on one side of the plate and one on the other side so that you can bolt two joints on either side as shown in the pictures.

    Next, cut a piece of 2XX3/16” rectangular tubing from a length long enough to go from one frame member to the other. The length of this needs to be the same as the width of your joints. In this case, it was 2 ½”. Center it over the welded on nut facing the inside of the vehicle, the one that is one inch up from the edge and 2 ½” from the edge as shown in the pic.

    Next you can trim up the plate to save some weight, although not necessary. Next cut another plate 8 ½X6” and place one leading even with the edge on the right. Drill a 9?16” hole that is in the same exact place as the upper right hand hole. The trailing edge should be about a half inch behind. Also cut a piece of 1/4X2” flat iron 6” long and place along the bottom so that the trailing edge of the flat iron is even with the trailing edge of the larger plate and drill two 3/8” holes through both plates 1” up from the bottom and ½” from the edge of the flat iron as shown in the pic.

    You can also trim to save weight as shown. Next place the plates together and run a bolt through a joint as shown and weld the plate to the square tubing. You now have half of your bracket and three inches of cross member. As you can guess, there was a reason for welding that lower nut in place. You cannot get a wrench on it. Make sure it is secure, but don’t distort the threads from too much welding.

    Now it is time to tack the bracket to the edge of the 4X16” plate. The center of the hole that is in the cross member should be lined up with a perpendicular line in the equidistant between the two holes in the plate and 1 ¾” up the bracket from the center of the hole. The idea is that the joint
    which is just over 3” in diameter, or a 11/2” radius will not bind on the frame when secured.

    After mounting the plate, it is necessary to check the top joint for clearance. So install the joint and rotate it. Mine had about 1/16” clearance, which is enough.

    Then cut a 1/4X3” flatiron 3 ½” long, just long enough to fit between the bolts on the 16” flat iron and not interfere. Drill a 9/16” hole 1 ¾” from the top and 1 ¾” from each edge and tack with a joint in place as shown. Next you can take it all down and tack in a 1/4X2 1/2X3” gusset in the rear behind the joint, making sure you don’t have any interference from the joint. Then weld it all together and paint the hard to get places. It should look like this when done.

    When installed, it should look like this.

    Now it is time to weld the long plate to the frame.

    Next is the links. The first thing is that whatever link you build, it will need to be adjustable. XJs aren’t entirely square, they can be a little out of adjustment. That is why they shim the lower links, to adjust the track. The classic question everyone asks is: How do I know long to make the links. The answer is that the bracket has to be in place first. They all you have to do is measure. You measure from the center of the eye on the lower link to the center of the bump stop, then subtract the distance from the center of the bump stop to the center of the eye on the lower link mount on the axel tube. That distance will have the lower spring mount centered when stuffed on to the bump stop as it was designed to be. The distance on mine is 32 ¼” So no to make the links. I bought a link kit from Parts Mike. Mike has really done his homework and come up with a line of products made for wheelers, since he is an old wheeler himself. Here is a finished link and the pieces next to it.

    Make sure you leave about ½” of threads left so you can shorten it a little if you need to. When you get your first link done, mount it.

    Next, you need to make your top link. It needs to be made a little different than the bottom. This link needs to have right and left hand threads so you can easily adjust your castor angle. If you have a custom axel in the front, you can just weld a couple of tabs on for another bushing or rod end. But if you have a standard D30 front end, it is a little more complicated. You have to come up with a good bushing for the standard hole. I have had trouble finding them. The rubber ones are not tough enough for a three link. So I made mine. I had a sleeve turned down from left over rod link tubing to fit the stock hole on the pumpkin. I then used a bushing from a Chevy K series front spring which just happens to fit the inside diameter of the DOM tubing. You can cut the bushings down with a hack saw to fit a standard 2” wide top link end, which I cannibalized from my last suspension. Otherwise you can build one from 1/4X2” flat bar.

    After you have made the end, the link needs to be welded up. It has a spherical rod end on it with a left hand thread. The left hand is important, because the other end needs to be made with some 1 1/4X12 all thread. I guarantee you that you will not find any left hand thread in that size laying around. I got mine at a machine shop. It is a common farm thread. My finished length ended up at about 30 ½” after adjustment for castor angle.

    When you have finished your top link, mount it, Remove your passenger side top link.
    and adjust your castor angle. In an XJ it should be in the neighborhood of 5°

    I used my Droid phone, which has an app for a level. I just put it on the top of the upper ball joint and adjusted the axle to 6°

    Now it is time to move to the passenger side of the vehicle. You already have a plate 16” long drilled for the cross member bolts. Now you need to make a decision. If you want a 4 link front, then you need to repeat the steps already mentioned and make a mirror image of the bracket on the driver side. If instead you are satisfied with as three link, as I am then you just need to cut two pieces of steel, one 1/4X6X2.5” for the inner part of the bottom link bracket and one the same size as the outer part of the lower link bracket and drill the same holes in the same places and weld these brackets in the same places as the other side. I elected to reuse the brackets I made with these relative dimensions that I used for my Y link that was on before.

    Now it is time for the cross member. In the previous part of this build, it was neglected for a reason. I elected to have a removable cross member that can be removed without dismantling my suspension and future skid plates that I can remove also for service and repair without affecting my suspension. So the cross member will bolt in between the two brackets that have been welded in place. Remember the little piece of 1/4X26” flat bar that was drilled to fit the driver side bracket? We haven’t used it yet, but now is the time. It is welded to one end of the cross member that needs to be drilled for the transmission mount in the same position as the stock cross member. If you have a three link as I do, then you need to make another flat plate the same size or out of 1/4X2 1/2X6” flat bar for the other end. The difference is that this one has to have a hole large enough to clear the nut for the bolt for the passenger side lower link.

    If you have any clearance issues for things like exhaust pipes, such as my 3” exhaust, now is the time to account for that in the new cross member. Welded up, it looks like this.

    Installed, it turned out like this.

    That completes the three link suspension. I did not address the track bar. I fabbed my own with the same rod ends used for the suspension build. One of the nice things about this type of situation with a double shear track bar is that you can tune your suspension by changing springs in about 20 minutes if you have air tools. Also, the three link puts less strain on the links, bushings and frame than a four link.
    Last edited by 4.3LXJ; 05-16-2018 at 05:39 PM.
    230 hp 4.3L Chevy
    Built 4L60E with manual lockout
    Atlas 4 speed
    Griffin radiator
    On board air
    Warn 9.5ti on custom bumper
    7.5" RE front and bastard pack rear on custom long arms
    30 gal gas tank
    And a bunch of other stuff

  2. #2
    Join Date
    Nov 2015

    Default Re: How to build a three or four link suspension

    This is exactly what a have been looking for, a write up of HOW someone went about building it not just what they did! I know this is an old thread, but do you have pics of the upper link?

    Sent from my SM-G900V using Tapatalk

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