Triangulated Rear 4-Link
Adjusters:
Center and nest the notched stud on the urethane bushing outer tube. Weld.
Bars:
Depending on the rear end used and the frame width, the upper bars might have to be shortened. We suggest tacking the urethane bushing outer tube to the bar until the required bar length is established in the mock-up stage. Then center and nest the notched end of the tube on the urethane bushing outer tube. Weld.
Lower frame bracket assemblies:
Space the two frame-bracket side plates (222012) using a urethane bushing inner sleeve and a piece of cereal box cardboard as a shim. This will let the urethane bushing slip between the plates easily.
The notch in the 3-sided frame plates goes towards the rear of the frame for bar clearance. Note the orientation of the side plates in the drawings.
Weld the two side plates to the frame plate.
Align the 3-holed block with the holes in the lower axle bracket plate using two 5/8” bolts.
The coil-over mounting bolts will work well.
Weld the block to the plate at the top and bottom.
Remove the bolts and clamp the plate to your bench with the block on top.
Bend the sides of the plate up to 90 degrees. Try not to over bend – the “bridges”
at each end of the slot could break. Use a square to check the bends.
Put a ½” bolt through the side plate holes. Use a urethane bushing inner sleeve as a spacer with a small piece of cereal box cardboard to add to the length of the spacer, as you did with the frame brackets above. (This picture shows a spacer doing the same job.)
Weld the corner-to-corner edges that were made when the sides were folded.
Installation suggestions:
We highly recommend mocking up all parts before doing the final welding. Tacks are much easier to clean up if changes have to be made.
The rear end should be in position, front-to-rear and side-to-side and the frame should be at ride height.
The shorter bars are the uppers and the longer bars are the lowers.
The adjustable ends can go at the front or rear of the bar. For mock up, assemble the adjusters in the bars with about 3 threads showing.
The lower bar frame brackets can go inside or outside the frame rails. If they are mounted outside the rails, be sure there is room to mount the coil-overs or air suspension and shocks.
The following set-up dimensions are with the frame and rear end at ride height.
The urethane bushing hole center for the front of the lower bar should be 5” lower than axle centerline height and 27-1/8” ahead of rear axle centerline.
Tack the frame brackets in place.
The lower rear axle brackets should be spaced apart the same distance as the frame brackets so the bars will be parallel when viewed from above.
The lower rear axle brackets should be installed on the rear axle tube with the rear bracket surface vertical. This is not necessarily at 90 degrees to the housing face. The pinion might be raised slightly.
Rear axle upper bracket plates are designed to mount the bar with the middle of the urethane bushing above rear axle centerline. One plate will face ahead and one will face back.
Assemble an upper bar with the adjuster. We like to press in just ½ of a urethane bushing and the inner sleeve. This is rigid enough for mock up, but easy to take apart for later painting or finishing. Put the rear axle bracket plates on one end and the frame plates on the other end. The frame plates can run back along the bar for now.
If your differential is offset, like 8” and 9” Fords, start mock up on the shorter side.
Nest the upper axle brackets above the rear axle tube and move the assembly along the axle tube until the frame end is close to the boxing plate. The center of the urethane bushing should be 2-1/8” higher than the rear axle centerline height. Position the bar away from the boxing plate far enough to get a wrench on the nut. (The nut should be on the “closed” or rear side of the angled frame bracket so the bolt can be removed.)
There are four identical plates that will weld to the frame boxing plates and position the front of the upper bars. These plates are referred to as the frame plates. All four plates will have to be trimmed to length, depending on your installation. The “rear frame plate” is the plate on the rear side of the front urethane bushing. The “front frame plate” is the plate on the front side of the front urethane bushing.
Determine the cut line for the rear upper frame plates.
The rear frame plates can be cut to length and tacked to the boxing plates using the mocked up bars for positioning.
Trim the front upper plates.
Use the off-cut from the rear frame plate to gusset both upper frame plates. Be sure to maintain clearance for the urethane bushing outer sleeve.
Finish all welding. Be sure the urethane bushings have been removed or they will melt.