Installation instructions for 1930-54 Plymouth / Dodge passenger car rear parallel leaf spring kit  

1)      Install front spring hangers on springs using provided bolts. Locate center bolt of spring on axle centerline. Clamp front hangers to frame rail bottoms, making sure they are in the same place on each side.

2)      Install rear shackles  and shackle mounts on springs. Clamp shackle hangers to bottoms of frame, with bottom of shackles leaning slightly to the rear (approximately 10 degrees). Make sure both sides are in the same place. Measure side to side to make sure springs are parallel with each other.

3)      Double check all measurements, then tack weld both front and rear hangers in place with several tack welds each. Remove shackles and springs, then fully weld hangers in place.

4)      After hangers have cooled, then reinstall springs and shackles. Set spring perches on center bolts. Set axle housing in place on perches, centering it side to side on springs. Install u-bolts and lower spring plates, snugging up bolts but not fully tightening them. Rotate pinion of axle up until it is in the same plane as the engine / transmission  centerline. In most cases this will mean that the pinion is up 4 degrees in the front. Tack weld perches to housing at each corner of each perch. Remove axle. Very slowly weld perches to housing ( weld no more than 1” at a time, skipping from side to side, letting housing cool to the touch before welding another 1”.

5)      Reinstall axle with u-bolts, tightening fully.

6)      Bolt shocks to lower spring plates. Note: shocks can be installed either in front or behind axle by swapping lower spring plates side to side. Put them where they will work best for your application. With shocks mounted to lower spring plates, bolt upper shock crossmember outer pieces to tops of shocks, slide center section of upper shock crossmember inside of each outer section, then telescope out to fit between frame rails. Locate crossmember up and down so that shocks will not bottom out going up or down. If necessary, install a rubber bumper stop above axle to limit travel.

7)      Torque all bolts to proper torque for each bolt size. Re-torque all bolts after 100 miles and again after 1000 miles.