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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC Suburban - 2WD 🢒 Suspension 🢒 Wheel Alignment 🢒 Frame Bracket Knock Out Removal

Frame Bracket Knock Out Removal C Model

Removal Procedure

Tools Required

J 38794 Knockout Removal Tool

    Important: As originally installed, the upper control arm cannot be adjusted for the caster or the camber. However, if the caster or the camber is measured and is out of tolerance, the caster and the camber can be set to the proper specifications.

  1. Raise the vehicle.
  2. Suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

    3. Important: The jack or the jack stand must remain under the lower control arm during the removal and the installation procedure in order to retain the lower control arm position.

  3. Support the lower control arms with a jack or the jack stands.
  4. Remove the tire and the wheel assembly.

    5. Object Number: 156347 Size: SH
  5. Remove the following parts from the upper control arm bracket (4):
    6. • The nuts (6)
    • The cams (5)
    • The bolts (1)

    Object Number: 156346 Size: SH
  6. Lift the upper control arm (3) up and to the side in order to gain access to the inner portion of the frame bracket.
  7. Use the J 38794 in order to remove the frame bracket knockout as follows:
    8. • Do not distort the frame bracket when removing the knockout.
    • Apply extreme pressure lubricant to the threads of the T-bolt.
    • Insert the bolt through the knockout hole in the bracket support.
    • Install the bridge onto the T-bolt.
    • The forward bracket requires the bridge to be installed between the legs of the bracket due to access problems.

       Notice: Do not subject the tool to more than 100 N·m (75 lb ft) torque. Exceeding the recommended torque may damage the tool and/or the bracket.

    • Assemble the following parts in order:
        1. The bridge
        2. The bearing with the chamfered side out
        3. The washer
        4. The nut
    • The T-bolt head and the bridge must line up horizontally with the knockout.
    • The bridge should span the knockout without interfering with the knockout procedure.
    • Tighten the T-bolt head against the knockout by turning the nut at the opposite end using a socket and torque wrench.
    • An open end wrench or adjustable wrench may be needed in order to prevent the T-bolt from losing the horizontal alignment with the knockout.
    • If the torque limit on the T-bolt is met and the knockout does not break free, use a die grinder of appropriate size.
    • Using the stamped outline as a guide, remove the knockout.
    • Remove the wax coating in the knockout area in order to make the perforation lines more visible.
    • If the outline is not visible, use the T-bolt head installed horizontally, as a template, and scribe the frame bracket.
    • Repeat the procedure on the other upper control arm frame bracket.

Installation Procedure

    Object Number: 156346 Size: SH
  1. Install the upper control arm (3) into the frame brackets (2).
  2. Install the bolts (1) and the cams (6) through the frame brackets (2) and through the control arm (3).
  3. Install the cams (6) and the nuts (4).

    4. Install the cams with the radius toward the frame brackets.

  4. Partially tighten the nut (4).
  5. Install the front wheel assemblies.
  6. Install the alignment machine heads.

    7. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

    Important: Verify alignment specifications before proceeding. Refer to Wheel Alignment Specifications in Wheel Alignment.

  7. Adjust the caster and the camber to the correct specifications by rotating the bolt head installed through the adjuster cam.

    8. Tighten

    1. Tighten the front upper control arm nuts (4) to 190 N·m (140 lb ft).
    2. Tighten the rear upper control arm nuts to 190 N·m (140 lb ft).
  8. Set the steering wheel on center with the wheels straight.
  9. Loosen the adjuster sleeve nuts.
  10. Adjust the toe-in. Refer to Fastener Tightening Specifications .

    11. Tighten
    Tighten the tie rod adjuster sleeve nuts to 19 N·m (14 lb ft).

  11. Ensure that the clamps are properly positioned. Refer to Tie Rod Adjuster Replacement in Steering Linkage.
  12. Recheck the alignment specifications.
  13. Lower the vehicle.

Frame Bracket Knock Out Removal K Model

Removal Procedure

Tools Required

J 38794 Knockout Removal Tool

  1. Raise the vehicle.
  2. Suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

    3. Important: The jack or the jack stand must remain under the lower control arm during the removal and the installation procedure in order to retain the lower control arm position.

  3. Support the lower control arms with a jack or the jack stands.
  4. Remove the tire and the wheel assembly.

    5. Object Number: 156347 Size: SH
  5. Remove the following parts from the upper control arm bracket (2):
    6. • The nuts
    • The cams (4)
    • The bolts (3)

    Object Number: 156348 Size: SH
  6. Lift the upper control arm (2) up and to the side in order to gain access to the inner portion of the frame bracket.
  7. Use the J 38794 in order to remove the frame bracket knockout as follows:
    8. • Do not distort the frame bracket when removing the knockout.
    • Apply extreme pressure lubricant to the threads of the T-bolt.
    • Insert the bolt through the knockout hole in the bracket support.
    • Install the bridge onto the T-bolt.
    • The forward bracket requires the bridge to be installed between the legs of the bracket due to access problems.

       Notice: Do not subject the tool to more than 100 N·m (75 lb ft) torque. Exceeding the recommended torque may damage the tool and/or the bracket.

    • Assemble the following parts in order:
        1. The bridge
        2. The bearing with the chamfered side out
        3. The washer
        4. The nut
    • The T-bolt head and the bridge must line up horizontally with the knockout.
    • The bridge should span the knockout without interfering with the knockout procedure.
    • Tighten the T-bolt head against the knockout by turning the nut at the opposite end using a socket and torque wrench.
    • An open end wrench or adjustable wrench may be needed in order to prevent the T-bolt from losing the horizontal alignment with the knockout.
    • If the torque limit on the T-bolt is met and the knockout does not break free, use a die grinder of appropriate size.
    • Using the stamped outline as a guide, remove the knockout.
    • Remove the wax coating in the knockout area in order to make the perforation lines more visible.
    • If the outline is not visible, use the T-bolt head installed horizontally, as a template, and scribe the frame bracket.
    • Repeat the procedure on the other upper control arm frame bracket.

Installation Procedure

    Object Number: 156346 Size: SH
  1. Install the upper control arm (2) into the frame brackets.
  2. Install the bolts and the cams (4) through the frame brackets and through the control arm (2).
  3. Install the cams (4) and the nuts.

    4. Install the cams with the radius toward the frame brackets.

  4. Partially tighten the nut.
  5. Install the tire and the front wheel assemblies.
  6. Install the alignment machine heads.

    7. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

    Important: Verify alignment specifications before proceeding. Refer to Wheel Alignment Specifications in Wheel Alignment.

  7. Adjust the caster and the camber to the correct specifications by rotating the bolt head installed through the adjuster cam.

    8. Tighten

    1. Tighten the front upper control arm nuts to 190 N·m (140 lb ft).
    2. Tighten the rear upper control arm nuts to 190 N·m (140 lb ft).
  8. Set the steering wheel on center with the wheels straight.
  9. Loosen the adjuster sleeve nuts.
  10. Adjust the toe-in. Refer to Fastener Tightening Specifications .

    11. Tighten
    Tighten the tie rod adjuster sleeve nuts to 19 N·m (14 lb ft).

  11. Ensure that the clamps are properly positioned. Refer to Tie Rod Adjuster Replacement in Steering Linkage.
  12. Recheck the alignment specifications.
  13. Lower the vehicle.