The 1965 Mustang was a sporty car that was built by Ford. Although the Mustang shared no exterior body panels with any other Ford car, the platform and mechanical components were shared with the Ford Falcon. The 1965 and 1966 Mustangs, like the Falcon, had a coil spring independent front suspension and a solid rear axle supported by leaf springs. To correct a sagging rear suspension on a 1965 Mustang, replacement of the leaf springs may be necessary.
Lift the rear of the Mustang with a floor jack and place a jack stand under each rear frame rail. Lower the floor jack so that the car's weight is supported by the jack stands. Place the floor jack under the center of the rear axle differential. Raise the jack so that the jack's lifting pad is just touching the differential.
Locate the spring shackles which attach the rearward end of the leaf springs to the frame rails. Remove the shackle retaining bolts by twisting them out with a socket and ratchet wrench. Slide the bolts out of the shackles, which separates the rearward end of the leaf springs from the frame.
Locate the upper rear shock absorber mounting bolts which are directly above the rear axle on each side. Loosen and remove the bolts with a socket and ratchet wrench. Remove the brake lines from the inner side of each rear wheel by twisting off the fittings with a tubing wrench.
Lower the floor jack slightly, which will lower both leaf springs and the rear axle together as assembly to create working room to remove the two front leaf spring retaining bolts. Remove the bolts with a socket and ratchet and slide them out of their mounting holes.
Lower the floor jack to its lowest setting. Locate the spring U-bolts that attach the leaf springs to the rear axle. Loosen and remove the U-bolt retaining nuts with a socket and ratchet. Lower the U-bolts and the leaf springs from the rear axle.
Hold the new leaf springs to the underside of the rear axle and replace the U-bolts and retaining nuts. Tighten the retaining nuts to secure the springs to the rear axle.
Raise the floor jack and line up the holes in the front of each leaf spring to the holes in the mounting brackets on the frame. Replace the original bolts and tighten them with a socket and ratchet.
Raise the floor jack further and line up the holes in the rearward end of the springs to the holes in the spring shackles. Replace the shackle bolts and nuts and tighten them. Replace the upper shock absorber mounting bolts and tighten them. Replace the brake lines and tighten the fittings with a tubing wrench. Raise the floor jack just high enough to remove the jack, then lower the car to the ground.
Bleed the rear brakes by loosening the bleed screw on the inner side of each rear wheel with a wrench. Push the hose from a brake bleeder onto one of the fittings, then pump the handle of the bleeder until clear brake fluid is seen coming through the hose. Pull the hose off and tighten the fitting. Repeat for the other rear wheel. Open the hood and remove the master cylinder cap. Add brake fluid to the reservoir until it reaches the full mark. Replace the cap and close the hood.
