GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2007 🢒 STS 🢒 Body Repair 🢒 Frame and Underbody 🢒 Rear Frame Replacement

Tools Required

J 39580 Engine Support Stand

Removal Procedure
  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Remove the rear suspension bracket. Refer to Rear Suspension Bracket Replacement .
  3. Remove the rear wheels. Refer to Tire and Wheel Removal and Installation .
  4. Remove the exhaust system. Refer to Exhaust System Replacement .
  5. Remove the driveshaft from the differential. Refer to Rear Propeller Shaft Replacement .

    6. Object Number: 708375 Size: SH

    Important: The lower control arms will drop approximately 3 inches when the shock to lower control arm bolts are removed.

  6. Install the support fixture (3), in order to raise the lower control arm to relieve the tension from the shock.
  7. Remove the shocks lower mounting bolt (2).
  8. Remove the support fixture.

    9. Object Number: 767222 Size: SH
  9. Disconnect the electrical connectors for the rear wheel speed sensors (WSSs).
  10. Disconnect the retainer clips on the park brake cables for the WSSs wiring harness.

    11. Object Number: 833131 Size: SH
  11. Disconnect the rear brake pipe lines (1) forward of the rear wheelhouse.

    12. Object Number: 833132 Size: SH
  12. Remove the fastener for the brake pipe bracket (1).
  13. Remove the brake pipe bracket (2) from the studs in the body.

    14. Object Number: 492729 Size: SH
  14. Disconnect the intermediate park brake cable (2) from the front park brake cable connector.

    15. Object Number: 751494 Size: SH
  15. Disconnect the intermediate park brake cable (2) from the rear park brake cable connector (1).
  16. Position the frame support table J 39580 .

    17. Object Number: 708181 Size: SH
  17. Remove the frame to body mounting bolts (4) and washers (3).

    18. Object Number: 801998 Size: SH
  18. Carefully raise the vehicle from the rear frame assembly.
  19. Remove the following components from the rear frame:
    20. •  Headlamp Leveling Rear Suspension Height Sensor Replacement
    •  Lower Control Arm Replacement
    •  Upper Control Arm Replacement
    • The rear brake pipes
    •  Parking Brake Rear Cable Replacement - Left Side or Parking Brake Rear Cable Replacement - Right Side
    •  Stabilizer Shaft Replacement
    •  Adjust Link Replacement
    •  Trailing Arm Replacement
    •  Stabilizer Shaft Link Replacement
    •  Rear Brake Caliper Replacement
    •  Rear Brake Rotor Replacement
    •  Differential Replacement
  20. With the aid from an assistant, remove the frame from the hydraulic jack.

Installation Procedure

    Object Number: 801998 Size: SH
  1. With the aid from an assistant, position and secure the new rear frame on the engine support fixture.
  2. Install the following components to the rear frame assembly:
    3. •  Differential Replacement
    •  Rear Brake Rotor Replacement
    •  Rear Brake Caliper Replacement
    •  Stabilizer Shaft Link Replacement
    •  Trailing Arm Replacement
    •  Adjust Link Replacement
    •  Stabilizer Shaft Replacement
    •  Parking Brake Rear Cable Replacement - Left Side or Parking Brake Rear Cable Replacement - Right Side
    • The rear brake pipes
    •  Upper Control Arm Replacement
    •  Lower Control Arm Replacement
    •  Headlamp Leveling Rear Suspension Height Sensor Replacement

    Important: The rear coil springs need to be indexed into the lower spring insulators prior to assembly.

  3. Index the rear coil springs to the spring insulators.

    4. Important: Ensure the intermediate brake cable is clear of the front frame to body mount prior to securing the frame bolts.

  4. Ensure the intermediate park brake cable is positioned over left side frame assembly on the left side.
  5. Lower the vehicle to the frame.

    6. Object Number: 725835 Size: SH
  6. Position the coil springs (3) to the upper spring insulator (2).

    7. Object Number: 708181 Size: SH
  7. Index the rear side frame mounts to the rear locator sleeves (1) located on the body.
  8. Lower the vehicle until the frame mounts contact the body rail.

    9. Notice: Refer to Fastener Notice in the Preface section.

  9. Install the rear frame washers (3) and anchor bolts (4).

    10. Tighten

        • Tighten the front bolts to 265 N·m (195 lb ft).
        • Tighten the rear bolts to 191 N·m (141 lb ft).
  10. Raise the vehicle.
  11. Remove the J 39580 .

    12. Object Number: 708375 Size: SH
  12. Install the support fixture (3) in order to raise the lower control arms for ease of lower shock bolt installation (2).
  13. Install the lower shock bolt.

    14. Tighten
    Tighten the bolt (2) to 150 N·m (111 lb ft).

  14. Repeat the above step for the other side.
  15. Remove the support fixture (3).

    16. Object Number: 751494 Size: SH
  16. Connect the intermediate park brake cable (2) to the rear park brake cable connector (1).

    17. Object Number: 492729 Size: SH
  17. Connect the intermediate park brake cable (2) to the front park brake cable connector.

    18. Object Number: 833132 Size: SH
  18. Position the brake pipe bracket (2) to the body studs.
  19. Install the brake pipe bracket retaining nuts (1).

    20. Tighten
    Tighten the nuts to 10 N·m (89 lb in).


    Object Number: 833131 Size: SH
  20. Connect the rear brake lines (1) at the forward rear wheelhouse.

    21. Tighten
    Tighten the lines to 15 N·m (11 lb ft).


    Object Number: 767222 Size: SH
  21. Connect the rear WSS electrical connectors.
  22. Secure the electrical harness retainer clips to the park brake cables.
  23. Install the rear wheels. Refer to Tire and Wheel Removal and Installation .
  24. Install the rear suspension bracket. Refer to Rear Suspension Bracket Replacement .
  25. Lower the vehicle.
  26. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding .
  27. Align the vehicle. Refer to Wheel Alignment Measurement .