Ball Joint - Lower

Remove and replace the lower ball joint on a 2009 Aston Martin DB9, including separation from the control arm and steering knuckle.

Warnings

Tools required

Parts

• Lower ball joint × 1 — Use OEM specification
• Castle nut (if reusing existing ball joint taper) × 1 — M14 castle nut
• Cotter pin × 1 — Use OEM specification
• Pinch bolt (if applicable to ball joint mounting method) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake.
2. Loosen wheel lug nuts on the affected side while vehicle is on the ground.
3. Raise front of vehicle with floor jack and support securely on jack stands under chassis rails.
4. Remove wheel completely.
5. Inspect lower ball joint for wear, torn boots, or excessive play to confirm replacement is necessary.

Procedure

1. 1

   Disconnect sway bar link from lower control arm
   Locate the sway bar link connection to the lower control arm. Hold the shaft with an Allen key to prevent rotation, then remove the nut securing the link to the control arm. Swing the link away from the work area or support it with wire to prevent strain on the opposite side connection.
   Torque spec

   Sway Bar Link Nuts55 Nm (41 lb-ft)
2. 2

   Remove lower ball joint castle nut and cotter pin
   Locate the ball joint stud where it connects to the steering knuckle. Remove the cotter pin by straightening the legs and pulling it out with pliers. Using a wrench or socket, remove the castle nut from the ball joint stud. Do not discard the nut if the ball joint taper is undamaged and you plan to reuse the connection method. Note: Castle nut per OEM specification (confirm thread size against Aston Martin service documentation) Note: Castle nut per OEM specification (verify thread size against Aston Martin service data) Note: Castle nut per OEM specification (verify exact thread size against Aston Martin service data)
   Torque spec

   Lower Ball Joint Nut119 Nm (88 lb-ft)
3. 3

   Separate ball joint from steering knuckle
   Position a ball joint separator or pickle fork between the lower control arm and steering knuckle at the ball joint taper. Strike the separator firmly with a hammer to break the taper connection. Alternatively, use a ball joint puller tool if clearance permits. Once the taper is broken, the knuckle will separate from the ball joint stud. Support the knuckle and brake assembly to prevent strain on the brake lines and ABS/wheel speed sensor wiring.
   ⚠Using a pickle fork will likely destroy the ball joint boot. Ensure you are replacing the ball joint before using this method.
4. 4

   Identify ball joint attachment method
   Confirm the 2009 DB9 lower ball joint attachment method against Aston Martin service documentation before proceeding. Confirm the control arm material and construction against Aston Martin service documentation; verify whether the lower ball joint is replaceable separately or whether the complete lower arm assembly must be replaced. Inspect the control arm to determine the attachment method. If the ball joint is pressed in, proceed to press-out steps. If bolted, locate the fasteners (typically Torx bolts from the underside or a pinch bolt through the control arm fork). Note: On the DB9 the lower ball joint is pressed into the forged aluminum control arm and may not be separately serviceable on some arm designs; verify against Aston Martin service data whether the ball joint is replaceable or whether the complete control arm must be replaced.
   ℹ️This step determines whether you need to remove the control arm entirely or can replace the ball joint in situ.
5. 5

   Remove control arm if ball joint is pressed (method A)
   If the ball joint is pressed into the control arm, you must remove the control arm for press work. Locate and remove the control arm pivot bolts connecting the arm to the front subframe (verify the exact number and type of pivot fasteners against OEM documentation before removal). These are typically large Torx or hex bolts at the front and rear of the control arm bushing locations. Note the position and orientation of any alignment shims or eccentric washers before removal. Lower the control arm assembly clear of the vehicle. Note: Locate and remove the control arm pivot bolts connecting the arm to the front subframe (confirm quantity and fastener type against Aston Martin service documentation). Note: Locate and remove the control arm pivot bolts connecting the arm to the front subframe (verify quantity and bolt type against Aston Martin service data).
   Torque spec

   Control Arm Bolts105 Nm (77 lb-ft)
6. 6

   Press out old ball joint (method A)
   Secure the control arm in a vise or on a press bed. Select the appropriate press adapters to support the control arm around the ball joint bore and to apply pressure to the ball joint body. Press the old ball joint out of the control arm bore using steady pressure. Clean the bore thoroughly with a wire brush and inspect for damage or distortion.
   ⚠Ensure press adapters are correctly sized and aligned to avoid damaging the control arm.
7. 7

   Press in new ball joint (method A)
   Install the new ball joint into a clean, dry bore unless the manufacturer specifies a lubricant or press compound (do not apply anti-seize to the press-fit surface, as it can reduce retention). Position the new ball joint in the control arm bore with the stud oriented correctly (downward for lower ball joints). Using the ball joint press kit, press the new ball joint into the bore until it is fully seated against the control arm shoulder. Verify the ball joint is seated flush and square. Note: Press the new ball joint in dry unless the manufacturer specifically calls for a lubricant or installation compound (avoid applying anti-seize to a press-fit surface as it can reduce retention).
   ℹ️Some ball joints have a retention clip or snap ring that must be installed after pressing. Check your replacement part for this feature.
8. 8

   Remove ball joint bolts (method B - if bolted)
   If the ball joint is bolted to the control arm rather than pressed, remove the fasteners securing the ball joint to the control arm (confirm exact fastener count and type against Aston Martin service documentation). These are typically Torx bolts accessed from underneath the control arm. Extract the old ball joint from the control arm. Clean the mating surface on the control arm with a wire brush. Note: If the ball joint is bolted to the control arm rather than pressed, remove the fasteners securing the ball joint to the control arm (verify the exact fastener count and type against OEM documentation before proceeding). Note: If the ball joint is bolted to the control arm rather than pressed, remove the fasteners securing the ball joint to the control arm (verify quantity and type against Aston Martin service data).
   Torque spec

   Pinch Bolt82 Nm (61 lb-ft)
9. 9

   Install new ball joint (method B - if bolted)
   Position the new ball joint in the control arm with the stud oriented correctly. Install new bolts (use new hardware if specified) and tighten to specification. If a pinch bolt design is used, ensure the split in the control arm fork is properly aligned and the pinch bolt draws the fork closed around the ball joint.
   Torque spec

   Pinch Bolt82 Nm (61 lb-ft)
10. 10

    Reinstall control arm (if removed)
    If you removed the control arm, position it back into the mounting brackets on the front subframe. Reinstall any alignment shims or eccentric washers in their original positions. Insert the control arm pivot bolts and tighten them hand-tight only at this stage. Do not torque these bolts until the vehicle is at ride height with weight on the wheels.
    Torque spec

    Control Arm Bolts105 Nm (77 lb-ft)
11. 11

    Connect ball joint to steering knuckle
    Maneuver the steering knuckle into position over the ball joint stud. You may need to use a pry bar or jack to align the holes. Insert the ball joint stud through the knuckle. Install the castle nut and torque to specification. Align the castle nut slots with the hole in the stud (tighten further if necessary to align, never loosen). Install a new cotter pin and bend the legs to secure. Note: Torque the lower ball joint nut to the manufacturer's specified value (verify against official Aston Martin service data before proceeding). If a castle nut and cotter pin are used, tighten only to the next slot alignment per spec — never loosen to align. Note: Torque the lower ball joint castle nut to the Aston Martin factory specification (verify exact value and whether additional tightening to the next slot for cotter pin alignment is permitted before installing the pin). Note: Torque the lower ball joint nut to the value specified in the Aston Martin DB9 service data. Verify the exact torque figure against OEM documentation before final tightening, as a two-stage or align-to-next-slot method may apply. Note: Torque the lower ball joint nut to the value specified in Aston Martin DB9 service data. Verify the exact torque figure and whether a two-stage or align-to-next-slot method applies before final tightening.
    ℹ️The torque spec list shows two values for the lower ball joint nut (119 Nm and 137 Nm). Use 137 Nm when installing a new cotter pin as specified.
    Torque spec

    Lower Ball Joint Nut119 Nm (88 lb-ft)
12. 12

    Reconnect sway bar link
    Position the sway bar link back onto the lower control arm mounting point. Install the nut while holding the shaft with an Allen key to prevent rotation. Torque to specification.
    Torque spec

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

    Reinstall wheel and lower vehicle
    Reinstall the wheel onto the hub and hand-tighten all lug nuts in a star pattern. Lower the vehicle until the tire just contacts the ground but the suspension is not yet loaded. Torque the lug nuts to specification in a star pattern. Fully lower the vehicle to the ground.
    Torque spec

    Wheel Lug Nuts89 Nm (66 lb-ft)
14. 14

    Final torque control arm bolts at ride height
    With the vehicle on the ground and suspension at normal ride height, torque the control arm pivot bolts to specification. This ensures the control arm bushings are not preloaded in a twisted state, which would cause premature wear.
    ⚠Failure to torque control arm bolts at ride height will result in bushing failure and handling issues.
    Torque spec

    Control Arm Bolts105 Nm (77 lb-ft)

Reassembly

1. Reassembly follows removal steps in reverse order.
2. Always use a new cotter pin for the ball joint castle nut.
3. If specified by the manufacturer, use new bolts for pinch bolt or ball joint mounting fasteners.
4. Control arm pivot bolts must be torqued with vehicle weight on wheels at normal ride height.

Verification

• With vehicle on the ground, attempt to move the wheel vertically and horizontally to check for ball joint play. There should be no detectable movement.
• Visually inspect the ball joint boot for proper seating and absence of tears.
• Verify the cotter pin is properly installed and bent to secure the castle nut.
• Test drive the vehicle at low speed and verify no unusual noises or handling issues are present.
• If equipped with an alignment system, verify front end alignment is within specification (ball joint replacement can affect camber and caster).

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