Ball Joint - Upper

This procedure replaces the upper ball joint on a 2009 Aston Martin DB9, requiring suspension disassembly to access and remove the upper control arm assembly.

Warnings

Tools required

Parts

• Upper ball joint × 1 — Use OEM specification
• Upper ball joint castle nut × 1 — Use OEM specification
• Cotter pin (for ball joint nut) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Loosen wheel lug nuts while vehicle is on ground
3. Raise front of vehicle and support securely on jack stands at manufacturer-specified jacking points
4. Remove front wheel
5. Apply penetrating oil to ball joint nut, control arm bolts, and sway bar link fasteners if corrosion is present

Procedure

1. 1

   Remove wheel speed sensor wire
   Locate the ABS wheel speed sensor wire routed from the steering knuckle/hub and any brackets securing it to surrounding suspension components. Release any clips or brackets securing the wire to prevent damage during disassembly. Move the wire clear of the work area.
2. 2

   Disconnect sway bar link from upper control arm
   Locate the sway bar (anti-roll bar) link connection. Verify whether it attaches to the upper control arm, lower control arm, or knuckle on the DB9. Hold the link shaft with an Allen key to prevent rotation, remove the nut securing the link, and swing the link clear of the work area.
   Torque spec

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

   Remove upper ball joint castle nut
   Remove the upper ball joint retaining nut from the ball joint stud. Note the exact fastener type used (self-locking nut or castle nut with cotter pin) before removal and replace with the correct OEM fastener. Do not reuse a self-locking nut or cotter pin. Note: Verify the ball joint stud retention type (castle nut with cotter pin vs. self-locking nut) against Aston Martin service data. If a castle nut is used, remove the cotter pin with pliers, then unscrew and remove the castle nut from the ball joint stud. Note: Remove the upper ball joint retaining nut from the ball joint stud. Verify whether the vehicle uses a self-locking nut (most likely on the DB9) or a castellated nut with cotter pin before ordering replacement hardware. Do not reuse a self-locking nut or cotter pin. Note: Upper ball joint retaining nut (verify castle nut vs. self-locking nut type against Aston Martin service data before ordering)
   Torque spec

   Upper Ball Joint Nut119 Nm (88 lb-ft)
4. 4

   Separate ball joint from steering knuckle
   Position a ball joint separator (press-type puller preferred on this aluminum suspension — avoid a pickle fork to prevent damaging the boot and aluminum components) between the upper control arm and steering knuckle at the ball joint taper. Apply steady pressure to break the taper fit and release the ball joint stud from the knuckle. Support the knuckle assembly to prevent it from dropping when the ball joint releases.
   ⚠The knuckle assembly will drop when the ball joint separates. Support it with a jack or secure it with wire to prevent brake hose damage.
5. 5

   Mark control arm position
   Before removing the upper control arm bolts, mark or photograph the positions of any alignment adjustment hardware (shims or eccentric cams, if present on the DB9) at the control arm mounting points to aid reassembly. Regardless, a full alignment will be required after this repair. Note: Before removing the upper control arm bolts, mark or photograph the position of any camber/caster adjustment hardware (eccentric cam bolts or shim packs, if present) at the control arm mounting points, verifying the actual adjustment arrangement against Aston Martin service data. Note: Before removing the upper control arm bolts, mark and record the position and thickness of any camber/caster adjustment shims at the control arm mounting points. Keep each shim pack with its corresponding bolt. This will aid in reassembly and reduce the need for full alignment adjustments.
6. 6

   Remove upper control arm mounting bolts
   Locate the upper control arm mounting bolts at the suspension tower or subframe. Verify the exact upper control arm mounting bolt count and fastener type against Aston Martin service documentation before proceeding. Remove these bolts and carefully lower the upper control arm from the vehicle. Note the position of any washers or spacers. Note: Locate the upper control arm mounting bolts at the suspension tower or subframe. Confirm the exact bolt count and fastener type against Aston Martin DB9 service documentation before removal. Remove the mounting bolts and carefully lower the upper control arm from the vehicle, noting the position of any washers or spacers. Note: Locate the upper control arm mounting bolts at the suspension tower or subframe. Remove the mounting bolts (verify exact count against Aston Martin service documentation before ordering hardware) and carefully lower the upper control arm from the vehicle. Note the position of any washers, shims, or spacers.
   Torque spec

   Control Arm Bolts105 Nm (77 lb-ft)
7. 7

   Press out old ball joint
   Verify against Aston Martin service documentation whether the upper ball joint is a separately serviceable pressed-in unit or integral to the upper control arm (which would require replacing the arm as an assembly). If pressable, secure the upper control arm in a hydraulic press or ball joint press, position the appropriate adapters to support the control arm around the ball joint housing, and press the ball joint out from below. Apply steady pressure until the ball joint is fully removed from the control arm bore. Clean the ball joint bore thoroughly with a wire brush, removing any corrosion or debris. Note: Verify whether the DB9 upper ball joint is a separately serviceable pressed-in component or integral to the upper control arm. If the ball joint is integral (as is typical for this platform's aluminum control arm), the complete upper control arm must be replaced as an assembly and this press-out step does not apply. Note: Verify whether the upper ball joint is separately serviceable on this vehicle. On the 2009 DB9 the upper ball joint is commonly integral to the forged aluminum upper control arm, in which case the complete control arm assembly must be replaced rather than pressing out the ball joint. If separate replacement is confirmed, secure the control arm in a press and use adapters that support the arm around the ball joint housing while pressing the joint out, then clean the bore of corrosion and debris.
8. 8

   Press in new ball joint
   If the ball joint is a serviceable pressed-in component, align the new ball joint with the control arm bore in the correct orientation, press against the housing only (never the stud), and seat fully to the same depth as the original. If the ball joint is integral to the control arm, omit this step and install the complete replacement control arm assembly.
9. 9

   Install upper control arm to vehicle
   Position the upper control arm back into its mounting location at the suspension tower. Install the control arm mounting bolts with any shims, washers, or spacers in their original positions as marked. Thread bolts finger-tight but do not torque at this time.
   ⚠Control arm bolts must be torqued with vehicle weight on wheels. Only snug bolts at this stage.
   Torque spec

   Control Arm Bolts105 Nm (77 lb-ft)
10. 10

    Connect ball joint to steering knuckle
    Raise the steering knuckle (use a floor jack if needed) to align the ball joint stud with the knuckle taper hole. Insert the ball joint stud fully into the knuckle. Install the new retaining nut and torque to specification. If the vehicle uses a self-locking nut, torque directly to the specified value; if it uses a castellated nut, tighten only as necessary to align the slots with the stud hole and install a new cotter pin, bending the ends to secure.
    Torque spec

    Upper Ball Joint Nut119 Nm (88 lb-ft)
11. 11

    Reconnect sway bar link
    Position the sway bar link back to the upper control arm mounting point. Install the nut, hold the link shaft with an Allen key to prevent rotation, and torque the nut to specification.
    Torque spec

    Sway Bar Link Nuts55 Nm (41 lb-ft)
12. 12

    Reinstall wheel speed sensor wire
    Route the ABS wheel speed sensor wire back along its original path and secure with any clips or brackets to the control arm or suspension components. Ensure the wire has adequate clearance from moving suspension parts and the tire.
13. 13

    Install wheel and lower vehicle
    Install the wheel and thread lug nuts hand-tight. Lower the vehicle until the tires just contact the ground but the suspension is still unloaded. Torque the wheel lug nuts in a star pattern to specification. Fully lower the vehicle so the suspension is at normal ride height with vehicle weight on the wheels.
    Torque spec

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

    Torque control arm bolts at ride height
    With the vehicle at normal ride height and weight fully on the wheels, torque the upper control arm mounting bolts to specification. This is critical to prevent premature bushing failure.
    ⚠Control arm bolts MUST be torqued at ride height with vehicle weight on wheels. Failure to do so will cause premature bushing wear and potential failure.
    Torque spec

    Control Arm Bolts105 Nm (77 lb-ft)

Reassembly

1. Reassembly follows removal in reverse order with the following critical exceptions:
2. Always use a new castle nut and cotter pin for the ball joint
3. Control arm mounting bolts must only be torqued to final specification when vehicle weight is on the wheels at ride height
4. Verify all ABS sensor wiring is secured and has clearance from moving components

Verification

• Verify the ball joint castle nut is torqued correctly and the cotter pin is properly installed and bent
• Check that all control arm bolts are torqued to specification with vehicle at ride height
• Verify wheel lug nuts are torqued to specification in a star pattern
• Test drive the vehicle at low speed and verify no unusual noises from the suspension
• Have a professional wheel alignment performed, as suspension geometry has been disturbed

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