Easy Street Kit for 1967-1972 Chevrolet C10 Part

Easy Street Kit for
1967-1972 Chevrolet C10
Part No. 75709 — Rear Suspension
MN-430
(01002)
NPR 2931
1. Begin the installation by elevating the truck, and placing it securely on jack stands. Ensure that you have jack stands forward of and behind the rear axle area. Remove the
wheels.
2. Place a floor jack under the rear axle assembly. Elevate the rear axle assembly slightly
and remove the shock absorbers.
3. Lower the rear axle assembly so that the springs are fully extended. Note: Do not allow
the rear axle to hang from the springs.
4. Remove the spring retaining bolts and clamps on the control arms.
See Figure A.
FIGURE A
5. Lower the rear axle.
6. Remove the spring retaining bolts and clamps on the frame. Remove the springs.
7. Remove the Panhard rod.
8. Remove the OEM jounce bumper, drill out the rivets, and remove the jounce bumper bracket.
See Figure B.
FIGURE B
9. Lift the upper air spring mount/c-notch bracket as close to the frame as possible, and identify
the rivets that must be drilled out. Note that two rivets securing the Panhard rod mount, on
the underside of the frame, must be removed.
10. Using a suitable marker, mark and trace the c-notch profile onto the frame. For reference, use
the jounce bumper nut, in the new mount, and locate it directly outboard the OEM bumper
mount holes. Remember that the frame dog-legs at this area, so the marks that you make on
the underside of the frame will NOT be 90° to the frame. It is best to make the marks undersize, and then grind the frame to fit after cutting.
See Figure C.
FIGURE C
11. Drill out the rivets identified in Step 9. (on the passenger side, the holes that correspond to
the Panhard rod mount rivets will be drilled out AFTER the air spring mount/c-notch is in
place).
12. Grind the outer lip of the OEM upper spring mount so that the outer edge of the frame is
flush, top to bottom.
See Figure D.
FIGURE D
13. Drill mounting holes in the frame that correspond to the upper corners of the c-notch relief
that you previously marked on the frame. Using a suitable tool (cut-off wheel), cut along
the marked lines identified in Step 9. so that the relief cuts intersect at the holes. Cut the
relief along the lines that you marked on the underside of the frame. Remove and discard
the relief section.
14. Temporarily fit the mount to the frame. Grind, as required, to fit. Ensure that the grinding
you perform on the c-notch relief allows for proper alignment of the reference (rivet) holes.
See Figure E.
FIGURE E
15. When you are satisfied with the fit, drill the remaining mounting holes, using the bracket as a
jig. Paint the frame cuts and install the bracket. Install the jounce bumper.
16 Repeat this process on the passenger side. Ensure that you drill the mounting holes on the
underside of the bracket.
17. Mount the lower air spring bracket to the control arm, using the original coil spring mounting
hole as a reference. Mark and drill the two gusset holes in the face of the arm (One hole
should line up with an OEM hole). Mount the bracket. Repeat on the passenger side.
See Figure F.
FIGURE F
18. Ensure that the floor jack is under the rear axle. Loosen the OEM u-bolts that retain the rear
axle, use the jack to raise the axle, and remove the drivers side lower shock mount and ubolt. Loosen the passenger side bolt, as required, to allow sufficient movement of the axle
to allow this.
19. Install the new lowering block, spacer plate, and new +” straight bolts. Note that the wedge
taper of the lowering block, should be oriented so that the lowest part is towards the front.
Install the nuts on the bolts loosely, but do not tighten.
20. Repeat this procedure on the passenger side. Instead of installing the spacer plate under
the lowering block, install the Panhard rod mount.
21. Install the passenger side lower shock bracket on the drivers side, and vice versa. Do this by
reversing the mounts so that the pins are facing inward, and forward. Relief grinding of the
mounts may be necessary to allow the shock to fit.
See Figure G.
FIGURE G
22. Install the new Panhard rod. Tighten all bolts
23 Install the shocks.
24. Install the air springs. Plumb per the Big Bore instructions.
See Figure H.
FIGURE H
25. An optional upper boxing plate is provided. This plate mounts above the c-notch opening,
on the inside of the frame, and must be welded into place.