Lower Control Arm - Rear

Remove and replace the rear lower control arm on a 2009 Aston Martin DB9, including disconnection from the knuckle and subframe mounting points.

Warnings

Tools required

Parts

• Rear lower control arm × 1 — Use OEM specification
• Lower ball joint nut (if damaged or single-use type) × 1 — Use OEM specification
• Control arm mounting hardware (if corroded) × 1 — Use OEM specification

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Chock front wheels securely
3. Loosen rear wheel lug nuts 1/4 turn while vehicle is on ground
4. Raise rear of vehicle and support securely on jack stands at manufacturer-specified jacking points
5. Remove rear wheel completely
6. Spray all suspension fasteners with penetrating lubricant and allow to soak 10-15 minutes

Procedure

1. 1

   Disconnect sway bar link from lower control arm
   Locate the sway bar link connection to the lower control arm. Hold the ball stud with an Allen key to prevent rotation, then remove the lower mounting nut using the appropriate socket. Separate the link from the control arm and secure it out of the way with wire or a bungee cord to prevent damage to the boot.
   Torque spec

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

   Support the rear knuckle assembly
   Position a floor jack under the rear knuckle/hub assembly with a block of wood to distribute load. Raise the jack just enough to take the weight of the knuckle and support the suspension at ride height position. This prevents the assembly from dropping when the control arm is disconnected and maintains proper geometry for reassembly.
3. 3

   Remove lower ball joint nut
   Locate the lower connection between the control arm and the rear upright/knuckle. Remove the nut or pinch bolt securing the control arm to the upright, noting the exact fastener type used on this vehicle. If a cotter pin is present, remove it first. Note the orientation for reassembly. Note: Locate the outboard connection between the control arm and the rear upright/knuckle. Depending on configuration this may be a ball joint stud or a bolted bushing connection. Remove the securing nut (and cotter pin if present). Verify the actual fastener type against Aston Martin service documentation before proceeding. Note the orientation for reassembly. Note: Verify the actual outboard connection type on the DB9 rear lower control arm against Aston Martin service documentation before proceeding. The DB9 rear suspension typically uses a bolted bushing/pivot connection to the upright rather than a tapered ball joint; confirm fastener type and remove accordingly. Note the orientation for reassembly.
   Torque spec

   Lower Ball Joint Nut63 Nm (46 lb-ft)
4. 4

   Separate ball joint from knuckle
   Confirm the outboard control arm-to-upright connection type against Aston Martin service documentation. If it is a tapered ball joint, use a ball joint separator to free the taper, avoiding damage to the stud threads. If it is a bolted bushing/pivot connection, simply withdraw the pivot bolt. Once freed, carefully lower the jack supporting the knuckle slightly to provide clearance for control arm removal.kle slightly to provide clearance for control arm removal.
5. 5

   Mark control arm position
   Before removing the control arm mounting bolts, inspect for eccentric washers, cam bolts, or slotted mounting holes that affect rear wheel alignment. If present, mark the position of all eccentric components relative to the subframe with paint or a scribe to preserve the current alignment settings. Photograph the installation for reference.
6. 6

   Remove front control arm mounting bolt
   Locate the front pivot bolt securing the control arm to the subframe or chassis mounting bracket. This bolt typically runs through a bushing in the control arm. Support the control arm with one hand or a jack, then remove the mounting bolt completely. The bolt may require significant force to break free due to thread-locking compound. Note the orientation of any washers or spacers on the bolt.
   Torque spec

   Control Arm Bolts165 Nm (122 lb-ft)
7. 7

   Remove rear control arm mounting bolt
   Remove the rear pivot bolt securing the control arm to the subframe or chassis. Confirm the correct bolt and orientation against Aston Martin service documentation before removal. As you remove this final bolt, support the control arm to prevent it from falling. Remove the control arm from the vehicle, maneuvering it past the brake components and suspension members as needed. Note: Refer to manufacturer documentation to confirm the correct pivot bolt and its orientation on the DB9 rear suspension. Note: Note the length and orientation of this bolt relative to the front pivot bolt for correct reinstallation.
   Torque spec

   Control Arm Bolts165 Nm (122 lb-ft)
8. 8

   Inspect mounting points and hardware
   With the control arm removed, inspect the subframe mounting holes and bushings for wear, corrosion, or damage. Clean the mounting bolt holes with a wire brush. Inspect the removed mounting bolts for thread damage or corrosion; replace if compromised. Check the ball joint taper seat in the knuckle for damage or wear. If the control arm is being reused, inspect bushings for cracking, tearing, or separation from the metal sleeves.
9. 9

   Install new control arm to subframe
   Position the new control arm into place, aligning the mounting holes with the subframe brackets. Insert the front mounting bolt first, threading it through the control arm bushing and subframe bracket. Do not tighten fully. Install the rear mounting bolt similarly, threading it through but leaving loose. If eccentric washers or cam bolts were present, install them in the marked positions from removal. Hand-tighten both bolts to hold the control arm in position.
   Torque spec

   Control Arm Bolts165 Nm (122 lb-ft)
10. 10

    Connect ball joint to knuckle
    Raise the floor jack supporting the knuckle to align the outboard control arm connection with the upright. Reconnect using the correct fastener type confirmed against Aston Martin service documentation (bolted pivot or ball joint stud). Tighten to specification, replacing any single-use self-locking nut with a new one. Ensure the connection is fully seated before final tightening.tening.
    Torque spec

    Lower Ball Joint Nut63 Nm (46 lb-ft)
11. 11

    Reconnect sway bar link
    Position the sway bar link into the mounting point on the lower control arm. Install the lower mounting nut while holding the ball stud with an Allen key to prevent rotation. Tighten to specification. Verify the link moves freely without binding.
    Torque spec

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

    Reinstall wheel and lower vehicle to operating height
    Install the rear wheel, threading all lug bolts by hand first to prevent cross-threading. Snug the lug bolts in a star pattern but do not fully tighten. Remove the jack stands and carefully lower the vehicle until the suspension is at normal operating ride height with full vehicle weight on the wheels. The suspension should be in its normal loaded position before final torquing of control arm bolts. Note: Correct socket for wheel lug bolts (verify size against manufacturer documentation)
    Torque spec

    Wheel Lug Nuts89 Nm (66 lb-ft)
13. 13

    Torque control arm mounting bolts
    With the vehicle weight on the wheels and suspension at ride height, torque the front and rear control arm mounting bolts to specification. This is critical: tightening these bolts with the suspension hanging or at full droop will preload the bushings and cause premature failure. Torque both bolts in the sequence they were installed (front first, then rear). Verify both bolts are secure.
    ⚠Control arm pivot bolts must be torqued at ride height with vehicle weight on wheels. Failure to do so will damage bushings and cause premature wear.
    Torque spec

    Control Arm Bolts165 Nm (122 lb-ft)
14. 14

    Final torque wheel lug nuts
    With the vehicle on the ground, torque all wheel lug bolts to specification in a star pattern. Perform a final check of all fasteners installed during this procedure.
    Torque spec

    Wheel Lug Nuts89 Nm (66 lb-ft)

Reassembly

1. Control arm mounting bolts must be torqued with vehicle at ride height and weight on wheels to prevent bushing damage
2. All fasteners should be checked for proper torque after initial test drive
3. If eccentric bolts or cam adjusters are present, alignment settings may have been disturbed and should be checked

Verification

• Test drive vehicle at low speed and verify no clunking, knocking, or unusual noises from rear suspension
• Verify steering remains centered and vehicle tracks straight with hands off wheel on level road
• Perform visual inspection of all reinstalled components for proper seating and torque
• Schedule four-wheel alignment to verify rear suspension geometry is within specification
• Re-torque all fasteners after 50-100 miles of driving as part of settling-in process

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