Upper Control Arm - Front

This procedure covers removal and installation of the front upper control arm on a 2009 Aston Martin DB9, including disconnection of the upper ball joint from the steering knuckle and control arm mounting points.

Warnings

Tools required

Parts

• Front upper control arm assembly × 1 — Use OEM specification
• Upper ball joint nut (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and apply parking brake.
2. Place wheel chocks behind rear wheels.
3. Loosen wheel lug nuts on the side being serviced while vehicle is on ground.
4. Raise front of vehicle and support securely on jack stands placed under manufacturer-recommended jacking points.
5. Remove front wheel completely.

Procedure

1. 1

   Access upper control arm area
   From the wheel well, locate the upper control arm assembly. The arm connects the upper ball joint at the steering knuckle to two mounting points on the chassis/subframe. Clean the area around all fasteners with a wire brush and apply penetrating oil to control arm mounting bolts and ball joint nut if corrosion is present. Allow penetrant to soak for 5-10 minutes.
2. 2

   Support steering knuckle assembly
   Position a floor jack under the lower control arm (which carries the spring/damper load) to support the assembly and prevent it from dropping when the upper ball joint is disconnected. Verify spring/damper mounting configuration against Aston Martin service documentation. Raise jack just enough to take light load off the suspension. Note: Position a floor jack under the lower control arm to support the assembly and control the spring/damper load before the upper ball joint is disconnected. Confirm the suspension spring load path on this double-wishbone setup before separating any joint.
3. 3

   Remove upper ball joint nut
   Locate the upper ball joint nut securing the ball joint stud to the steering knuckle. Confirm the exact nut type (castle nut with cotter pin or standard nut) against OEM documentation; if a cotter pin is present, remove and discard it. Using a breaker bar and appropriate socket, remove the upper ball joint nut completely. Keep nut for inspection; replace if threads are damaged.
4. 4

   Separate upper ball joint from knuckle
   Using a ball joint separator tool or pickle fork, separate the upper ball joint taper from the steering knuckle. Position the tool between the control arm and knuckle, taking care not to damage the ball joint boot. Strike the tool sharply or apply steady pressure until the taper releases. Alternatively, strike the side of the knuckle boss with a brass hammer while applying upward pressure to shock the taper loose. Once separated, lower the floor jack slightly to allow the knuckle to drop away from the control arm.
5. 5

   Remove front control arm mounting bolt
   Locate the front mounting bolt securing the control arm to the chassis/subframe. This bolt passes through the forward bushing of the control arm. Verify the fastener type against the vehicle; it may be a hex-head bolt rather than Torx. Select the correct socket after inspection. Using a breaker bar and appropriate socket, remove the front mounting bolt completely. Note the position and orientation of any washers or spacers. Note: Verify the exact fastener head type against OEM documentation before selecting a socket. Note: Verify the fastener head type against the Aston Martin workshop manual before selecting a socket; do not assume a specific drive type.
6. 6

   Remove rear control arm mounting bolt
   Locate the rear mounting bolt securing the control arm to the chassis/subframe. This bolt passes through the rearward bushing of the control arm. Using a breaker bar and appropriate socket, remove the rear mounting bolt completely. Note the position and orientation of any washers or spacers. The control arm should now be free from the vehicle.
7. 7

   Remove upper control arm
   Carefully maneuver the control arm out of the wheel well. Depending on clearances, it may be necessary to angle or rotate the arm to clear the shock/damper tower, brake lines, and other components. Inspect the removed control arm bushings and ball joint for wear, cracking, or damage. Inspect mounting points on chassis for damage or elongated bolt holes.
8. 8

   Prepare new control arm
   Unpack the new control arm and verify it matches the removed part in configuration and mounting points. Inspect ball joint boot for damage from shipping. Check that all bushings are properly seated and oriented. Ensure the ball joint taper and threads are clean and dry. Do not apply anti-seize or lubricant to the tapered joint, as this can prevent proper seating and affect torque accuracy.
9. 9

   Install new control arm to chassis
   Maneuver the new control arm into position in the wheel well. Align the front bushing with the front chassis mounting point and insert the front mounting bolt finger-tight. Align the rear bushing with the rear chassis mounting point and insert the rear mounting bolt finger-tight. Do NOT torque these bolts at this time—they must be torqued at ride height with vehicle weight on wheels.
10. 10

    Connect upper ball joint to knuckle
    Raise the floor jack under the lower control arm to lift the steering knuckle up to the upper ball joint stud. Align the ball joint taper with the hole in the knuckle. The taper should seat with moderate hand pressure or light tapping. Install the upper ball joint nut and tighten to the manufacturer-specified torque (verify value in Aston Martin DB9 service documentation). If OEM documentation specifies a castle nut with cotter pin, align to the next slot and install a new cotter pin; if a prevailing-torque (self-locking) nut is specified, replace it with a new nut. Note: Install the upper ball joint nut and tighten to the OEM-specified torque value (confirm against Aston Martin service documentation for the 2009 DB9). Note: Install the upper ball joint nut and tighten to the manufacturer-specified torque per the Aston Martin workshop manual (verify value before assembly).
    Torque spec

    Upper Ball Joint Nut60 Nm (44 lb-ft)
11. 11

    Reinstall wheel
    Clean the wheel hub mating surface and wheel mounting surface. Install the wheel and thread lug nuts by hand. Tighten lug nuts in a star pattern until wheel is seated against hub, but do not torque to final specification yet.
12. 12

    Lower vehicle to ground
    Carefully lower the vehicle from jack stands until full vehicle weight is resting on the wheels (ride height position). The suspension must be at normal ride height for proper bushing torque. Do not allow suspension to hang free when torquing control arm bolts.
13. 13

    Torque control arm mounting bolts
    With the vehicle at ride height and weight on wheels, torque the front control arm mounting bolt to specification. Then torque the rear control arm mounting bolt to specification. This sequence ensures the bushings are torqued in their natural operating position, preventing premature wear.
    Torque spec

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

    Torque wheel lug nuts
    Torque all wheel lug nuts to specification in a star pattern. Make two complete passes to ensure even seating and accurate torque.
    Torque spec

    Wheel Lug Nuts89 Nm (66 lb-ft)

Reassembly

1. Control arm mounting bolts MUST be torqued with vehicle weight on wheels at ride height, not with suspension hanging.
2. Install wheel and torque lug nuts in star pattern to ensure even seating.
3. Verify ball joint nut is torqued to specification and properly seated.

Verification

• With vehicle on ground, grab the top of the tire and attempt to rock it in and out. Excessive play indicates loose ball joint or mounting bolts.
• Visually inspect all fasteners to confirm they are fully tightened and washers/spacers are properly positioned.
• Test drive vehicle at low speed in a safe area and listen for clunking or knocking from front suspension.
• Have front end alignment checked and adjusted by a qualified technician as soon as possible after control arm replacement.

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