Upper Control Arm - Rear

This procedure covers removal and replacement of the rear upper control arm on a 2009 Aston Martin DB9, including suspension disassembly, control arm extraction, and reassembly with proper torque specifications.

Warnings

Tools required

Parts

• Rear upper control arm × 1 — Use OEM specification
• Upper ball joint nut (if damaged) × 1 — Use OEM specification
• Control arm mounting bolts (if damaged) × 2 — Use OEM specification

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Loosen rear wheel lug nuts 1/4 turn while vehicle is on ground
3. Raise rear of vehicle and support securely on jack stands at manufacturer's designated jacking points
4. Remove rear wheel on side being serviced
5. Apply penetrating oil to control arm mounting points and ball joint connection, allow 10-15 minutes to penetrate
6. Mark control arm orientation relative to chassis mounting points for installation reference if possible

Procedure

1. 1

   Support suspension assembly
   Position a hydraulic jack under the rear lower wishbone or hub assembly at a verified safe load point to support the weight of the suspension. Raise slightly to compress suspension approximately 1-2 inches from full droop. This relieves tension on the upper control arm and prevents the suspension from dropping when the upper arm is disconnected.
2. 2

   Disconnect upper ball joint from knuckle
   Locate the upper control arm connection at the top of the rear upright. Determine the connection type (tapered ball joint stud with nut, or pinch-bolt clamp) before proceeding. If a tapered ball joint is present, remove the securing nut and use a ball joint separator tool to break the taper connection between the ball joint stud and the upright; if a pinch-bolt clamp is used, remove the pinch bolt and spread the clamp to release the stud. Insert the separator tool between the knuckle and control arm ball joint housing, then tighten or strike according to tool type until the joint separates. Avoid hammering directly on suspension components.
   Torque spec

   Upper Ball Joint Nut60 Nm (44 lb-ft)
3. 3

   Access front control arm mounting bolt
   Locate the front mounting point of the upper control arm where it attaches to the chassis/subframe. This is typically a through-bolt with nut; note that the DB9 may use shims or eccentric adjusters for alignment, so verify the specific adjustment mechanism against OEM documentation and record its exact position before removal. Note the orientation of any eccentric washers or adjustment mechanisms before removal. You may need to access the nut from inside the wheel well or from underneath depending on design.
4. 4

   Remove front control arm mounting bolt
   Using a breaker bar and socket, remove the front control arm mounting bolt and nut. If eccentric washers or camber adjustment mechanisms are present, note their exact orientation and position. The bolt may be tight due to load and corrosion; use penetrating oil and allow time to work if necessary. Support the control arm as the bolt is removed to prevent it from dropping.
   Torque spec

   Control Arm Bolts85 Nm (63 lb-ft)
5. 5

   Access rear control arm mounting bolt
   Locate the rear mounting point of the upper control arm at the chassis/subframe. This may be positioned behind other components. Check for any heat shields, brake lines, or ABS sensor wiring that may need to be moved aside for access. Clear any obstructions without disconnecting brake hydraulics.
6. 6

   Remove rear control arm mounting bolt
   Remove the rear control arm mounting bolt and nut using appropriate sockets. Again note the position of any adjustment washers or spacers. With both mounting bolts removed, the control arm should be free from the chassis. Carefully extract the control arm from the vehicle, maneuvering around any brake components or suspension parts.
   Torque spec

   Control Arm Bolts85 Nm (63 lb-ft)
7. 7

   Inspect mounting points and hardware
   Inspect the control arm mounting bushings in the chassis for wear, cracking, or deformation. Check the mounting bolt holes in the chassis for elongation or damage. Inspect the removed hardware for thread damage or excessive corrosion. Examine the ball joint connection point on the knuckle for wear or damage. Clean mounting surfaces with a wire brush to remove corrosion and debris.
8. 8

   Install new upper control arm
   Position the new upper control arm into the mounting location, aligning the ball joint stud with the hole in the top of the knuckle. Insert the ball joint stud into the knuckle and thread the castle nut or securing nut onto the stud by hand. Do not fully tighten yet. Align the control arm with the front chassis mounting point.
9. 9

   Install front mounting bolt
   Insert the front mounting bolt through the control arm and chassis bushings, ensuring any eccentric washers or adjustment mechanisms are oriented exactly as noted during removal. Thread the nut onto the bolt by hand. Do not torque yet; leave fasteners loose to allow suspension geometry to settle.
   Torque spec

   Control Arm Bolts85 Nm (63 lb-ft)
10. 10

    Install rear mounting bolt
    Insert the rear mounting bolt through the control arm and chassis bushings, ensuring proper orientation of any washers or spacers. Thread the nut onto the bolt by hand. Leave loose at this stage.
    Torque spec

    Control Arm Bolts85 Nm (63 lb-ft)
11. 11

    Torque upper ball joint nut
    With the ball joint stud fully seated in the knuckle taper, torque the upper ball joint nut to the factory-specified value (verify against Aston Martin DB9 workshop manual before assembly). If using a castle nut with cotter pin, torque to specification then advance to the next cotter pin hole if necessary. Do not back off the nut to align the pin hole. Note: torque the upper ball joint nut to the OEM-specified value (verify against Aston Martin DB9 service documentation before tightening)
    Torque spec

    Upper Ball Joint Nut60 Nm (44 lb-ft)
12. 12

    Lower suspension to ride height
    Carefully lower the jack supporting the suspension until the suspension is at normal ride height (simulating vehicle weight on wheels). This can be achieved by reinstalling the wheel and lowering the vehicle to the ground, or by using a load simulator. The control arm mounting bolts MUST be torqued with suspension at ride height to prevent bushing bind.
13. 13

    Torque control arm mounting bolts
    With the suspension at ride height and vehicle weight on the wheels (or simulated), torque both the front and rear upper control arm mounting bolts to the factory-specified value and torque-angle (if applicable) as given in the Aston Martin DB9 workshop manual. Torque in the sequence: front bolt first, then rear bolt. Torque in the sequence: front bolt first, then rear bolt. This ensures proper bushing alignment and prevents premature wear. Note: torque both the front and rear upper control arm mounting bolts to the OEM-specified value (verify against Aston Martin DB9 service documentation before tightening)
    Torque spec

    Control Arm Bolts85 Nm (63 lb-ft)
14. 14

    Reinstall wheel and lower vehicle
    If the wheel was removed for final torquing, reinstall the wheel and hand-tighten lug nuts in a star pattern. Lower the vehicle to the ground. Torque wheel bolts to the factory specification (verify exact value against Aston Martin DB9 service documentation) in a star pattern to ensure even seating. Note: Torque wheel bolts to the OEM-specified value (verify exact value against Aston Martin DB9 service documentation) in a star pattern to ensure even seating. Note: Torque wheel bolts/nuts to the OEM-specified value in a star pattern to ensure even seating (verify against Aston Martin DB9 service documentation).
    Torque spec

    Wheel Lug Nuts89 Nm (66 lb-ft)

Reassembly

1. Reassembly follows removal steps in reverse order
2. Always torque control arm mounting bolts with vehicle weight on suspension
3. Ensure all eccentric washers and adjustment mechanisms are returned to original positions
4. Verify ball joint nut is properly torqued and secured

Verification

• Verify all fasteners are torqued to specification and no hardware is missing
• Check that the upper control arm moves freely through suspension travel without binding
• Verify no contact between control arm and other suspension or chassis components through full suspension articulation
• Test drive vehicle at low speed in a safe area and verify no unusual noises or handling issues
• Schedule four-wheel alignment immediately - suspension geometry has been disturbed and alignment is required

Related trouble codes on this vehicle

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