Lateral Arm

Replace the rear lateral arm (lower control arm) on a 2009 Aston Martin DB9, including removal of suspension components and proper torque procedures.

Warnings

Tools required

Parts

• Rear lateral arm (lower control arm) × 1 — Use OEM specification
• Control arm mounting bolts (if corroded) × 2 — Use OEM specification
• Ball joint pinch bolt or castle nut (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and chock front wheels
2. Loosen rear wheel lug nuts while vehicle is on ground
3. Raise rear of vehicle and support securely on jack stands at manufacturer jacking points
4. Remove rear wheel on side being serviced
5. Apply penetrating oil to lateral arm bolts and ball joint connection, allow to soak 10-15 minutes
6. Spray brake components with brake cleaner to avoid contamination during work

Procedure

1. 1

   Support rear suspension
   Position a floor jack under the rear suspension lower arm / hub carrier to support suspension weight. Verify in the Aston Martin DB9 workshop manual whether the coil spring/damper seats on this arm before relying on the jack to control spring load. Raise jack just enough to slightly compress suspension and take load off mounting bolts. This prevents suspension from dropping when arm is disconnected. Note: Position a floor jack under the rear lower control arm (lateral arm) near the wheel hub to support the suspension. Verify the DB9 spring/damper mounting location before relying on the arm to control spring tension.
2. 2

   Disconnect sway bar link (if present)
   If the sway bar (anti-roll bar) link attaches to the lateral arm on this vehicle, locate the link connection point (verify actual drop-link attachment point against DB9 documentation). Hold the internal shaft with an Allen key to prevent rotation, then remove the retaining nut using a socket. Disconnect the sway bar link from the lateral arm. Note the washer and bushing arrangement for reinstallation.
   Torque spec

   Sway Bar Link Nuts55 Nm (41 lb-ft)
3. 3

   Remove ball joint connection at hub
   Locate the lateral arm ball joint connection at the rear hub carrier. Remove the fastener securing the ball joint to the hub carrier (verify exact fastener type and size against Aston Martin DB9 workshop manual). Use a ball joint separator tool to break the taper connection between the ball joint and hub carrier. Insert the separator carefully to avoid damaging the hub carrier or ball joint boot. The ball joint should separate with moderate pressure. Note: Remove the fastener securing the ball joint to the hub carrier (verify exact fastener type and size against Aston Martin DB9 workshop documentation before proceeding). Note: Fastener type and torque must be verified against the Aston Martin DB9 workshop manual for the rear lateral arm ball joint connection; do not use estimated or cross-platform values
4. 4

   Mark alignment reference
   Before removing the lateral arm mounting bolts, use a paint pen or scribe to mark the position of any eccentric washers, cam bolts, or shims at the chassis mounting points. These components provide alignment adjustment. Photograph the installation for reference during reassembly.
5. 5

   Remove rear chassis mounting bolt
   Locate the rear mounting bolt securing the lateral arm to the chassis or subframe. This is typically the larger diameter bolt toward the rear of the vehicle. Using a breaker bar and the appropriate socket (verify hex, Torx, or E-Torx size against DB9 documentation), remove the rear mounting bolt completely. Support the arm with your hand as you remove the bolt to prevent it from dropping. Note: Torque the chassis mounting bolts per the sequence specified in the Aston Martin DB9 workshop manual; if no sequence is specified, torque both to specification evenly. Note: size to be verified against Aston Martin DB9 workshop documentation
6. 6

   Remove front chassis mounting bolt
   Locate the front mounting bolt securing the lateral arm to the chassis or subframe. Remove this bolt using the appropriate socket. Lower the floor jack slowly while guiding the lateral arm out of its mounting position. The arm should pivot free once both chassis bolts are removed.
7. 7

   Remove lateral arm from vehicle
   With both mounting bolts removed and ball joint disconnected, maneuver the lateral arm out from the suspension area. You may need to angle or rotate the arm to clear brake lines, ABS sensors, or other components. Inspect the removed arm for wear, cracks, or damaged bushings to confirm replacement is necessary.
8. 8

   Clean mounting points
   Use a wire brush to clean the chassis mounting points where the lateral arm bolts attach. Remove rust, dirt, and corrosion from bolt holes and mounting surfaces. Clean the hub carrier ball joint taper bore with a clean cloth. Inspect mounting hardware for thread damage or corrosion; replace bolts if threads are compromised.
9. 9

   Install new lateral arm
   Position the new lateral arm into the suspension area, aligning the ball joint with the hub carrier taper. Insert the ball joint into the hub carrier taper and install the pinch bolt or castle nut finger-tight. Align the lateral arm chassis mounting points with the subframe brackets.
10. 10

    Install chassis mounting bolts finger-tight
    Insert both front and rear chassis mounting bolts through the lateral arm bushings and into the subframe brackets. Align any eccentric washers or cam bolts according to your reference marks from removal. Thread bolts finger-tight only at this stage. Do NOT torque these bolts yet—they must be torqued with vehicle weight on suspension.
11. 11

    Torque ball joint connection
    Torque the ball joint pinch bolt or castle nut to the value specified in the Aston Martin DB9 workshop manual for the hub carrier ball joint attachment. Do not use estimated or cross-platform values; verify the exact specification before torquing. Ensure the ball joint taper is fully seated in the hub carrier before torquing. Ensure the ball joint taper is fully seated in the hub carrier before torquing. Note: Torque the ball joint pinch bolt or castle nut to the DB9-specific value from the Aston Martin workshop manual for the hub carrier ball joint attachment. Ensure the ball joint taper is fully seated in the hub carrier before torquing. Note: Torque the ball joint pinch bolt or castle nut to the specified value for this chassis connection (verify exact specification for DB9 hub carrier ball joint attachment against Aston Martin workshop documentation before torquing).
12. 12

    Reconnect sway bar link
    If a sway bar link was disconnected, reconnect it to the lateral arm. Install any bushings and washers in their original orientation. Hold the internal shaft with an Allen key and torque the retaining nut to specification.
    Torque spec

    Sway Bar Link Nuts55 Nm (41 lb-ft)
13. 13

    Reinstall wheel and lower vehicle
    Reinstall the rear wheel and hand-tighten lug nuts in a star pattern. Remove jack stands and carefully lower the vehicle until the suspension is at normal ride height with full vehicle weight on the wheels. The suspension must be loaded before final control arm bolt torque.
14. 14

    Final torque control arm bolts
    With vehicle weight on wheels (either on ground or on ramps at ride height), torque both lateral arm chassis mounting bolts to specification. This ensures the control arm bushings are torqued in their normal operating position, preventing premature bushing failure. Torque the chassis mounting bolts per the sequence specified in the Aston Martin DB9 workshop manual; if no sequence is specified, torque both to specification evenly.
    Torque spec

    Control Arm Bolts100 Nm (74 lb-ft)
15. 15

    Torque wheel lug nuts
    Torque the wheel lug nuts to specification in a star pattern. Perform a final visual inspection of all connections.
    Torque spec

    Wheel Lug Nuts89 Nm (66 lb-ft)

Reassembly

1. Control arm chassis bolts MUST be torqued with vehicle weight on suspension to prevent bushing bind
2. Verify all eccentric washers and alignment shims are in their original positions
3. Double-check that sway bar link is properly connected and torqued
4. Schedule a four-wheel alignment after lateral arm replacement—camber, toe, and thrust angle will be affected

Verification

• Test drive vehicle at low speed and verify no clunking or suspension noise from replaced lateral arm
• Check for proper wheel tracking and absence of pull to one side
• Re-torque wheel lug nuts after 50-100 miles of driving
• Have four-wheel alignment performed by qualified facility with Aston Martin specifications
• Visually inspect lateral arm mounting bolts and ball joint connection for proper seating after first drive

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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