Isuzu Cars and Trucks 1981-1991

Upper Control Arms

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REMOVAL AND INSTALLATION
RWD I-Mark and Impulse
  1. Raise the car and support it safely. Remove the front wheel.
  2.  
  3. Remove the upper brake caliper bolt and slide the brake hose retainer clip back about 1 / 2 in. (13mm).
  4.  
  5. Remove the lower shock bolt and push the shock absorber up.
  6.  
  7. Place a hydraulic jack under the control arm on the outer extreme and raise the control arm until it is level.
  8.  
  9. Loosen the upper ball joint lock nut until the top of the nut is flush with the top of the ball joint. Disconnect the upper ball joint from the steering knuckle using tool J26407 or equivalent.
  10.  
  11. Disconnect and remove the through bolt connecting the upper control arm to the crossmember. Remove the upper control arm.
  12.  



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Fig. Removing the upper control arm from the crossmember RWD I-Mark and Impulse



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Fig. Installation of the upper control arm RWD I-Mark and Impulse

To install:

  1. Install the upper control arm and install the through bolt connecting the upper control arm to the crossmember. Do NOT tighten at this time.
  2.  
  3. Install the upper ball joint lock nut until the cotter pin slot is in alignment. Torque the bolt to 20 ft. lbs. (25 Nm) and install a new cotter pin.
  4.  
  5. Install the lower shock bolt.
  6.  
  7. Install the upper brake caliper bolt and slide the brake hose retainer clip into retainer.
  8.  
  9. Install the front wheel and lower the vehicle.
  10.  
  11. Installation is the reverse of removal. On installation, make sure the smaller washer is on the inner face of the front arm and larger washer is on the inner face of the rear arm.
  12.  
  13. With the vehicle resting on the suspension torque the upper control arm through bolt to 65 ft. lbs. (88 Nm).
  14.  


NOTE
Always check the camber when working around the upper control arm area.

All Trucks

NOTE
The upper control arm and ball joint are replaced as an assembly on some vehicles.

  1. Raise and safely support the vehicle on the lower control arms.
  2.  
  3. Remove the wheel and tire assembly.
  4.  
  5. Remove the cotter pin nut fastening the upper control arm and upper ball joint assembly and disconnect the upper control arm from the steering knuckle.
  6.  


NOTE
Do not allow the steering knuckle to hang by the flexible brake line. Wire the steering knuckle up to the frame temporarily.

  1. Remove the bolts from the upper pivot shaft and remove the upper control arm from the bracket. Be sure to note the position and number of shims used for adjusting the camber and caster angles when removing the upper control arm. The shims must be replaced in their original position.
  2.  
  3. To remove the pivot shaft and bushings from the upper control arm assembly, remove the bushing nuts from the pivot shaft by loosening them alternately, then remove the pivot shaft.
  4.  

To install:

  1. To install the upper control arm and ball joint assembly, first install the pivot shaft boots to the pivot shaft.
  2.  
  3. Fill the internal part of the bushings with grease and screw the bushings into the pivot shaft. Be sure to screw the right-side and the left-side bushings alternately into the pivot shafts carefully avoiding getting grease on the outer face of the bushings. Tighten the nuts to 250 ft. lbs.
  4.  


NOTE
Be sure that the control arm and bushings are centered properly and that the control arm rotates with resistance but not binding on the pivot shaft when tightened to the proper torque.



Click image to see an enlarged view

Fig. Steering knuckle and control arm 2WD trucks



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Fig. Exploded view of the steering knuckle and control arm assemblies 4WD trucks

To install:

  1. Install the grease fittings and lubricate the parts with grease through the grease fittings.
  2.  
  3. Install the ball joint stud through the steering knuckle. Install the castellated nut and tighten it to 75 ft. lbs. and just enough additional torque to install the cotter pin. Use a new cotter pin.
  4.  
  5. Mount the upper control arm to the chassis frame and install the shims in their original positions between the pivot shaft and bracket. Tighten the pivot shaft attaching nuts to 55 ft. lbs.
  6.  


NOTE
Tighten the thinner shim pack's nut first for improved shaft-to-frame clamping force and torque retention.

  1. Install the dust cover.
  2.  
  3. Install the wheel assembly and lower the vehicle.
  4.  

 
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