Ladder bars are designed to give better traction on the rear wheels by efficient weight transfer. They prevent wheel hop associated with hard acceleration. To install ladder bars it will be necessary to use a welder that generates at least 130 amps for good penetration--a mig or stick welder. If you are installing these on a leaf spring suspension you will need a floater for the axle housing to prevent binding. If it is a coil spring suspension you will need to add a panard bar to locate the axle's center line.
Raise and support the vehicle on stands and level all four corners. To find the center line of the vehicle, take a plum bob and hang it on the inside edge of the front of the frame rail. At this point make a mark on the floor. Take the plum and move it to the farthest rear point of the frame and make a point on the floor. Do the same thing to the other side.
Secure a chalk line on the left side of vehicle forward of the front mark. Line the chalk line up with the second rearmost mark and extend the line slightly past the axle housing. Snap the line and do the same for the other side.
Hold a straightedge on top of the axle housing and against the tire. Tires and wheels can have different offsets and you want the ladder bar to be as far outboard as possible, leaving a minimum of 1 inch for tire flex. With the straightedge level and against the tire, mark the axle at this point. Now measure 1 inch inboard away from the tire and make another mark. Hang the plum from this spot and mark its position on the floor. Do the same to the other side.
Measure the distance between the first chalk line and the mark that you just made. Measure and mark two more spots forward and parallel to the chalk line. Hold the chalk line over the new marks and snap a new line parallel to the old line. Do the same for the opposite side.
Jack the axle housing up as far as it will go without lifting the car off the jack stands. It should be in its natural riding position.
Install the large bracket with holes for two bolts on the back section of the ladder bar and install the bolts and just snug the nuts down. Install the spherical end with the lock nut in the other end and turn it in five threads. Lock it down with the lock nut. Do the same for the other side.
Hold the crossmember for the ladder bar up between the frame rails and make sure it fits without modification. If it does not fit, measure between the middle lines and use that measurement to cut the crossmember to fit.
Get a long screwdriver or rod about 1 1/2-feet long. Hold the ladder bar against the axle housing with the outside of the bracket just touching the mark that is 1 inch in from the tire. Hold it up to the center of the frame rail; the bottom of the ladder bar should be parallel with the floor. Put the rod through the spherical hole and line it up with the center of the frame rail. Make sure it is straight and mark on both sides and the bottom of the ladder bar where it connects to the axle housing. Support and lightly tack weld the ladder bar to the axle housing. Do the same to the other side. The crossmember has been positioned.
Locate the tab or piece that is intended to attach the ladder bar to the crossmember. Install it (with the bolt provided) in the spherical end of the bar. Hold it out straight and butt the crossmember up against the loose tab. Mark the crossmember for welding. Make sure that it is centered in the frame rail and does not interfere with the floor. Tack weld in place. Repeat for the other side.
Remove the tabs from the ends of the bars and position them on the crossmember one half the bolt hole lower than the bar and tack weld in place. This puts 3 degrees of preload on the axle. When installed on the crossmember you want to see only the bottom half of the hole in the spherical end. Very slightly push down on the bar to insert the bolt.
Lower the axle housing and weld the crossmember and attachment tab in place. Install the safety cover over the bottom of the tab on the crossmember and weld in place or bolt on depending on type that came with the kit.
Remove the axles and bearings (to prevent damage). Weld the bar's forward plate in place. Weld the rear half at the center seam on both sides and 2 inches in the back. Clean and paint all welded surfaces.
Tighten all bolts. Use washers on both sides of the bolt in the spherical end.
Install the floating axle carrier in the event it is a leaf spring suspension or the panard bar in a coil spring application. The ladder bars can be adjusted by simply loosening the lock nut on the spherical end and turning the end in or out, hence increasing or decreasing the preload on the axle.
