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Torsion Bar and Lower Control Arm

REMOVAL & INSTALLATION

Fig. 1: Exploded view of the torsion bar removal/installation for 1986 trucks

Fig. 2: Matchmark all components — anchor arm-to-torsion bar shown

Fig. 3: Matchmarking the anchor bolt prior to removal for ease of re-assembly

Fig. 4: Measuring ball joint preload

Fig. 5: Removing and installing the ball joint dust boot — always inspect all parts for wear and visible damage, and replace as needed

Fig. 6: Installing the ball joint on the lower arm

Fig. 7: Torque plate installation

Fig. 8: Connecting the tension rod and stabilizer link

Fig. 9: Connecting the torsion bar to the torque plate — align the matchmarks made prior to disassembly

Fig. 10: Anchor arm positioning for installation when matchmarks aren't present

Fig. 11: Measuring points for ride height

Fig. 12: After removing the cotter pin, loosen the lower ball joint-to-control arm nut — do NOT remove the nut unless the lower control arm is safely supported

1986 Vehicles

NOTE: Special tools are necessary for this procedure.

  1. Raise and support the front end on jackstands under the frame.
  2. Remove the wheel.
  3. Remove the cotter pin and nut from the lower ball joint.
  4. Remove the lower shock absorber bolt.
  5. Matchmark the anchor arm bolt and anchor swivel and remove the bolt and swivel.
  6. Matchmark the torsion bar and anchor arm and the torsion bar and torque plate.
  7. Remove the anchor arm and torsion bar from the torque plate. Separate the anchor arm from the torsion bar.
  8. Unbolt and remove the torque plate.
  9. Remove the lower arm-to-frame bolt. Separate the lower arm from the frame bracket with bushing puller/installer 49 0727 575.
  10. Unbolt the tension rod from the lower arm and frame and remove it.

    NOTE: Don't change the position of the double nut at the rear of the tension rod bushing, since it would affect caster.

  11. Remove the stabilizer bar bolt, bushing, retainer and nut and remove the stabilizer bar.
  12. Using a ball joint separator, separate the lower ball joint from the knuckle. Remove the lower control arm.
  13. Inspect all parts for wear or damage. Replace any suspect parts. Using a spring scale and adapter 49 0180 510B, check the ball joint preload. Pull scale reading should be 39.6 lb. or less. Measure the preload after first shaking the ball joint stud 3 or 4 times to make sure it is free. To install:
  14. Install the lower arm on the frame bracket and hand-tighten the nut.
  15. Install the lower ball joint on the knuckle and torque the nut to 115 ft. lbs. Install the cotter pin.
  16. Tighten the lower arm-to-frame nut to 115 ft. lbs.
  17. Position the torque plate and tighten the bolt to 68 ft. lbs.
  18. Coat the splines on the torsion bar with lithium based wheel bearing grease. Check the ends of the torsion bar. The bars are marked L for left and R for right. Don't confuse them. Align the matchmarks and install the torsion bar in the torque plate.
  19. Coat the splines on the torsion bar with lithium based grease. Align the matchmarks and install the anchor arm on the torsion bar.
  20. Install the anchor bolt and swivel and tighten the bolt until the matchmarks are mated.
  21. Install the tension rod. Torque the bushing end nut to 90 ft. lbs.; the lower arm end bolts to 85 ft. lbs.
  22. Install the stabilizer bar. Torque the bolt to 19 ft. lbs.
  23. Install the shock absorber bolt. Torque the bolt to 55–59 ft. lbs.
  24. Install the wheels and lower the truck to the ground.
  25. Retorque the lower arm-to-frame bracket nut.
  26. Check the front and rear tire pressures. Set the pressures to what are specified on the vehicle rating plate, except for P-metric radials. Set them at the maximum pressure shown on the side wall.
  27. Measure the distance from the center of the wheel hub to the lip of the fender. This is the ride height. Proper ride height is obtained when the difference between the left and the right side is less than 10mm (0.394 in.). Adjust the ride height by turning the anchor bolt.

    NOTE: If, for some reason, you didn't matchmark the torsion bar anchor bolt, or the matchmarks were lost, or you're installing a new, unmarked torsion bar, here's a procedure to help you attain the correct ride height:

    1. Install the anchor arm on the torsion bar so that there is 125mm (4.92 in.) between the lowest point on the arm and the crossmember directly above it.
    2. Tighten the anchor bolt until the anchor arm contacts the swivel. Then, tighten the bolt an additional 45mm (1.77 in.) travel.

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