Classic Performance Products 175 East Freedom Avenue Anaheim, CA 92801

1947-'54 Chevy Pick Up Rear Leaf Spring Kit


'35-'48 leaf springs   


3/8-24xl-1/4" bolts   

1/2-20x4" bolts

leaf spring brackets

5-hole plates

3/8-24 nylox nuts

1/2-20 nylox nuts

shackle brackets

spring pads

3/8" flat washers

1/2" flat washers

'35-'48 shackles


7/16-20 nylox nuts

5/8-18x4-1/2" bolts

shackle pins

shock cross member

7/16-20x5" bolts

5/8-18 nylox nuts

shackle bushings

shock studs

7/16" flat washers (4) 5/8 flat washers

Installation Notes:


While it may be possible to install this kit without removing the bed, it is recommended that you do so, as it is much easier. Support the front and rear of the chassis on jack stands. Be safe! Avoid pulling and pushing on the vehicle while it is off the ground.


Remove the rear axle, springs, and brackets. To remove the rivets holding the brackets, grind the rivet heads flush. Center punch the rivet and drill through using progressively larger drills up to a 5/16" drill. The rivet should be relatively easy to punch out. If it is not, then continue drilling with a 3/8" drill. Take care not to drill the original rivet holes larger or off center, as you will be locating your now parts with these holes.


Install the leaf spring brackets on the outside and underside of each rail(the three holes on the sides attach in the same manner as the originals and two bottom holes line up with the rivet holes just drilled out). The running board brackets will have to be dimpled to clear the spring brackets. This can be done using a hammer and punch set to push the running board bracket flange away from the rail. Fasten the brackets to the rails using the 3/8-24xl-1/4" bolts, nylox nuts, and one washer under each nut. It may be necessary to align-drill a couple of these holes. In addition, there is another hole on the bottom of the bracket that requires the rails to be drilled. Use the bracket as a template for locating this hole. There should now be 6 bolts holding on each bracket.


Install the shackle brackets. The brackets are orientated on the rails, such that the side with the weld is on the inside of the rail. Line up the brackets with the holes of the original brackets. It may be necessary to align-drill a couple of these holes. Use three 3/8-24x1-1/4" bolts, nylox nuts, and one washer under each nut to fasten each bracket.


Weld spring pads an the axle. The spring centers are 39.75" and should angle the pinion 5º up. Most people will skip this step for right now.


Install the springs. Use the 1/2-20x4" bolts and nylox nuts to fasten the front of the spring into the front brackets. To make things easier, you may want to put the rear-end on a floor jack and roll it into position, keeping it raised and out of the way of the springs. Place the shackle bushings into the spring eyes and the shackle bracket. Slide the shackle pins through a shackle dog-bone and the bushings. Raise the rear of the spring and attach to the bracket using the shackle dog-bones and nylox nuts.


Set the rear-end onto the springs with spring pads in between. Center the rear-end and clamp the axle to the springs using the u-bolts, the 5-hole plates, and 1/2-20 nylox nuts. The 5-hole plates are positioned under the spring with the shock tabs pointing down on the inboard side and behind the axle. Typically, the spring pads are 5º down from the pinion, but just get this close for right now. Later, the final step will be to set the vehicle on the ground and to check that the pinion angle is 1º lower than the transmission angle. The pads can be welded on after the spring pad angle has been checked and repositioned if necessary.


Draw a line 28-1/8" in front of the rear bed bolt hole on top of each rail. Center the shock cross member an the top of the rails and mark the hole centers on the lines just drawn. Drill holes through the rail perpendicular to the surface. It is best to drill only the top of the rails and then set the cross member in place and use a transfer punch to mark the hole centers on the bottom of the rail.


Install the shock cross member with the shock mounting tubes pointing forward and parallel to the ground using the 5/8-18x4-1/2" bolts and nylox nuts with washers under the bolt heads and nuts. Fasten the shock studs to the 5-hole plates using the 1/2-20 nylox nuts. Install the shocks with the remaining fasteners.


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