How To Install A Performance Rear Suspension

It's good to check out the chassis mount's preliminary fitment, but have another person hold it in place or use a pair of C-clamps to secure the U-brackets to the framerails. This is done so other measurements can be made, such as the distance from a string hung from the axle to the inner face of the forward rod-end mount of the chassis mount.

With the chassis mount held in place, mark the location of the four pre-drilled holes in the U-brackets onto the framerails. Then remove the chassis mount to center-punch and drill 1/8-inch pilot holes. At this point, only drill the pilot holes through the outside of the framerails.

Drill the outside of the framerails to 5/8 inch. It's suggested to drill in stages, such as 3/8, 1/2, then 5/8 inch. Use sharp drill bits and keep them cool with spray lubricant while drilling.

Here's how the finished holes on the outside of the framerails should look.

The supplied frame insert tubes must be cut to the proper length. Determine the length by inserting a screwdriver through the first set of holes until it bottoms against the inner side of the framerail. Some cars will have extra pieces of sheetmetal inside the rail. If any of the insert tubes contact one of these pieces, be sure to measure the more shallow depth for proper fitment of the frame inserts. Record the depth by marking the screwdriver as shown (making sure to use the outside edge of the framerail), then transfer the measurement to the appropriate tube.

Cut each tube 1/16- to 1/10-inch shorter than the mark. This gives a slight crush to the framerail when the bolts are tightened and ensures the mount will be tight when installed. Label each insert for the right and left side of the car and indicate which end is toward the front or rear. Don't be surprised if all four tubes are cut to a different length; this is what makes the chassis mount a custom installation.

Install the inserts into the framerail as shown. Be sure to install them as they were initially marked: right and left, fore and aft. This one is marked "DS" for "driver side." The arrow refers to the side of the insert that needs to be on top. Next, clamp it in place with C-clamps.

Pass a 3/8-inch drill bit through the framerail insert tubes and drill a hole through the inner side of the frame. After drilling the first hole on the inside of the rail, place a bolt all the way through the insert and the inner side of the rail to ensure the insert stays in alignment while the second hole is drilled. Do this for both sides of the chassis mount.

Remove the bolts and deburr the holes. Reinstall the chassis mount with the frame inserts in place, again using C-clamps. Insert a bolt through each of the predrilled holes in the U-bracket, through the frame inserts and the holes that were drilled through the inner side of the framerails. The bolts will bottom out against the undrilled inner flange of the U-brackets. As shown here, remove one of the four bolts and pass the 3/8-inch drill bit through the holes in the outer flange of the U-bracket and through the frame insert tube; then drill through the inner flange chassis mount's U-bracket. Deburr the hole and blow out all the shavings from between the U-bracket and framerail. Reinstall the bolt with washers and a Nylock nut, and lightly tighten. Proceed with drilling the other three holes by removing one bolt at a time, drilling the holes in the U-bracket, then reinstalling the bolt. Drilling the holes this way will keep the chassis mount in proper alignment.

Due to Ford production tolerances, the width of the framerails in each car can vary. If your car's rails are considerably narrower than the chassis-mount U-brackets, use the provided spacer plates between the framerails and the flange of the U-brackets. This reduces how far they have to pinch inward when the bolts are tightened. These plates may or may not need to be used on the inboard sides of the framerails. Our car needed a plate on each of the outside flanges of the U-brackets, but not the inside. After all the holes are drilled and necessary spacer plates are in place, torque the 3/8-inch bolts to 47 lb-ft. The frame inserts allow these bolts to be firmly tightened without collapsing the framerails.

With the axle and chassis mounts installed, reinstall the springs, shocks, and wheels. Drive the car around the block to settle the suspension before installing the Panhard rod. During the installation of the Panhard rod, the rear suspension must be loaded with the weight of the car. Attach one rod end to the axle mount using the shorter 5/8-inch bolt and three 5/8-inch washers. One washer is placed on each side of the rod end and the third washer goes underneath the head of the bolt. Adjust the length of the rod by holding the unattached rod end so it doesn't turn, then twist the rod. When the assembly is the correct length, the longer 5/8-inch bolt will easily pass through the chassis mount's two elongated slots and the rod end, as shown here. Install the chassis mount's 5/8-inch bolt and use four washers: one on each side of the rod end (inside the mounting bracket) and two outside the bracket, one on each side. Adjust the height of the rod end in the slot so the rod is parallel to the ground. Note that the ride height of the car and how level the rod is will change with the addition of the driver and fuel load. Adjust the height of the rod with the driver in the car and with at least half a tank fuel. After the length and height of the rod are adjusted, torque the two 5/8-inch rod bolts to 115 lb-ft.

Complete the installation by tightening the jam nuts on the rod ends while holding the rod by the machined flats. Be sure the rod ends are in line with each other. If they're not, the rod will have its ability to move restricted, which would lead to binding as the suspension moves.