Subframe

Complete removal and replacement of the front or rear subframe assembly on a 2009 Aston Martin DB9, including suspension, drivetrain, and steering component disconnection.

Warnings

Tools required

Parts

• Subframe assembly (front or rear as required) × 1 — Use OEM specification
• Subframe mounting bolts (set of 4-6) × 1 — Use OEM specification
• Lower control arm bushings (if replacing) × 4 — Use OEM specification
• Steering rack mounting hardware × 1 — Use OEM specification
• Brake line clips and fasteners × 1 — Use OEM specification
• Anti-roll bar link bolts × 2 — Use OEM specification
• Engine oil drain plug washer × 1 — Use OEM specification
• Differential drain plug washer (rear subframe) × 1 — Use OEM specification

Fluids

• 5W-30 engine oil — 10.5 qt
• 75W-140 synthetic gear oil (rear subframe only) — 1.8 qt
• DOT 4 low-viscosity brake fluid — 1 qt
• CHF 11S power steering fluid — 1.2 qt

Preparation

1. Position vehicle on four-post lift with all wheels accessible. Ensure lift arms contact manufacturer-specified jacking points on chassis rails.
2. Disconnect battery negative terminal and wait 5 minutes for airbag system capacitor discharge.
3. Remove front or rear wheels as applicable using proper lifting procedure. Store lug nuts in labeled container.
4. Remove engine undertray panels by removing Torx fasteners around perimeter. Undertray is typically multi-section construction.
5. If removing front subframe: drain engine oil completely into suitable container. If removing rear subframe: drain rear differential oil.
6. Photograph all brake line routing, wiring harness positions, and suspension geometry from multiple angles for reassembly reference.
7. Support engine/transmission assembly from above using engine support bar or hoist attachment to prevent drivetrain sag when subframe is removed.

Procedure

1. 1

   Disconnect steering system (front subframe only)
   Mark steering shaft-to-rack pinion alignment with paint marker. Remove steering column intermediate shaft lower pinch bolt (typically E-Torx). Carefully separate intermediate shaft from steering rack pinion. Remove steering rack mounting bolts securing rack to subframe—verify exact bolt count and access points against the workshop manual. Initially leave hydraulic lines connected and support rack assembly with mechanic's wire; disconnect power steering lines later in Step 8 only if the rack must be fully removed with the subframe. Note: Verify steering intermediate shaft pinch bolt torque against Aston Martin workshop specification Note: Verify steering rack mounting bolt count and drive type/size against Aston Martin workshop documentation Note: Remove steering rack mounting bolts securing rack to subframe—verify exact count and access per OEM workshop manual before removal. Note: Verify exact bolt count and drive type/size against Aston Martin workshop manual Note: manufacturer specification (verify against Aston Martin workshop manual)
2. 2

   Disconnect brake lines and ABS sensors
   With ignition off, relieve residual brake system pressure before opening any hydraulic connections per OEM procedure. Cap all open lines immediately. Using flare nut wrenches, disconnect brake hard lines at subframe junction points—typically at flexible hose-to-hard line connections near shock towers. Cap all open lines immediately. Disconnect ABS wheel speed sensor wiring connectors and unclip harnesses from subframe routing channels. Note exact routing for reassembly.
3. 3

   Disconnect sway bar links
   Remove anti-roll bar (sway bar) end link connections at both sides. Hold link shaft with Allen key while removing upper nut to prevent spinning. End links typically connect to lower control arms or directly to subframe brackets. If bar is subframe-mounted, mark bar position relative to subframe bushings before proceeding.
   Torque spec

   Sway Bar Link Nuts55 Nm (41 lb-ft)
4. 4

   Disconnect lower control arms from knuckles
   At each side, remove lower ball joint pinch bolt or castle nut securing control arm to steering knuckle. Use ball joint separator tool or pickle fork to release taper fit. Apply penetrating oil if joint is seized. Strike knuckle boss (not ball joint stud) with brass hammer to break taper. Once separated, support control arms to prevent over-extension of bushings.
5. 5

   Disconnect strut/shock lower mounts
   Remove lower strut-to-knuckle mounting bolts at each side. These are typically large diameter bolts (2 bolts per side) passing through knuckle and strut bracket. Note that camber adjustment may be accomplished via eccentric bolts or slotted holes at this location—mark position before removal. Once bolts are removed, support knuckle assembly to prevent damage to CV axle or driveshaft.
   Torque spec

   Strut Bolts156 Nm (115 lb-ft)
6. 6

   Disconnect driveshafts or half-shafts
   For front subframe: no driveshafts or half-shafts are present (the DB9 is front-engine, rear-transaxle RWD). Skip driveshaft disconnection for front subframe work. For rear subframe: mark driveshaft/output-flange-to-transaxle alignment and disconnect as required. Support axles with mechanic's wire to prevent overextension. For rear subframe: mark half-shaft output flange alignment and remove flange mounting bolts after verifying exact bolt count against the Aston Martin workshop manual. Support the propshaft/torque tube assembly and secure it to the chassis to prevent strain on the torque tube and transaxle mounting during removal. Note: For front subframe: no driven half-shafts are present (DB9 is RWD) — skip axle disconnection. For rear subframe: mark driveshaft-to-transaxle flange alignment and the half-shaft/output flange bolt counts, and verify exact bolt counts against the workshop manual before removal. Note: Support the propshaft/torque tube and secure to chassis per workshop manual to prevent damage; note the DB9 uses an enclosed torque tube rather than a conventional open driveshaft with center support bearing. Note: For the front subframe on this RWD DB9 there are no driveshafts or half-shafts to disconnect. For the rear subframe: mark driveshaft-to-differential flange alignment and remove driveshaft mounting bolts (verify exact count per OEM manual). Support driveshaft and secure to chassis to prevent damage. Note: Verify exact flange bolt count per side against Aston Martin workshop manual
7. 7

   Disconnect exhaust system at subframe
   Remove exhaust system hangers and mounting brackets attached to subframe. For front subframe work, this typically includes catalytic converter support brackets. Use penetrating oil on exhaust fasteners and expect corrosion. Support exhaust system with jack or hanger straps to prevent stress on manifold connections. Oxygen sensor wiring may need to be unclipped from subframe.
8. 8

   Disconnect power steering lines (front subframe only)
   Place drain pan under power steering connections. Disconnect power steering pressure and return lines from steering rack or where they route through subframe. Verify line connection type (banjo bolts with crush washers or threaded fittings) against the workshop manual before removal. Cap all openings immediately to prevent contamination. Expect significant fluid drainage—have minimum 1 quart capacity in drain pan. Note: If the rack must be fully removed with the subframe, place a drain pan under the power steering connections and disconnect the pressure and return lines per OEM procedure. Verify fitting type before removal. Cap all openings immediately to prevent contamination.
9. 9

   Position subframe support fixture
   Position transmission jack or dedicated subframe support fixture under center of subframe. Adjust height until fixture makes solid contact with subframe and takes slight load. Secure subframe to fixture using straps or chains to prevent shifting during removal. Verify fixture is centered and stable before proceeding—subframe weight varies depending on attached components — verify weight and ensure support equipment is rated accordingly.
10. 10

    Mark and remove subframe mounting bolts
    Using paint marker, mark exact position of subframe relative to chassis at all four corners. The DB9 subframe is located by large through-bolts; verify the exact number and location of main mounting points against Aston Martin workshop documentation before removal. Check for additional support brackets or crossmembers. Remove subframe mounting bolts in sequence: start with rear bolts first, then front bolts, lowering fixture gradually (1-2 inches at a time) as each bolt is removed. Inspect for hidden brackets or wiring harnesses that may still be attached. Note: Verify subframe mounting bolt torque against Aston Martin workshop specification (do not rely on an estimate — aluminum chassis is intolerant of over-torque) Note: The DB9 subframe is located by main mounting bolts; verify the exact count and locations of mounting points against the Aston Martin workshop manual before removal. Note: The DB9 subframe is located by large mounting bolts; verify the exact number and location of main mounting points against the OEM workshop manual before removal. Note: Verify exact subframe mounting bolt count and locations (main vs auxiliary) against Aston Martin workshop manual Note: manufacturer specification (verify against Aston Martin workshop manual — do not rely on estimate)
11. 11

    Lower and remove subframe assembly
    Carefully lower subframe on support fixture, checking for any remaining connections at 6-inch intervals. Guide subframe past brake components, suspension parts, and body structure. Subframe may require angling or rotation to clear chassis rails and bodywork. Once fully lowered, roll fixture away from vehicle and inspect subframe for damage or wear requiring service.
12. 12

    Inspect and clean mounting surfaces
    With subframe removed, inspect chassis mounting points for corrosion, cracks, or damage. Clean all subframe mounting surfaces on both chassis and subframe using wire brush and degreaser. Inspect subframe bolt holes for thread damage or elongation. Check control arm bushings, transaxle/rear subframe mounts (rear), and engine mounts (front) for deterioration. Replace any compromised bushings or mounts before reinstallation.

Reassembly

1. Position new or serviced subframe on support fixture and raise into approximate position. Align subframe using reference marks made during disassembly before starting any bolts.
2. Install subframe mounting bolts finger-tight in all positions before torquing. Torque subframe bolts to manufacturer specification in diagonal sequence (cross-pattern) to ensure even seating. Verify alignment marks match before final torquing.
3. Reconnect all suspension components following reverse order of removal. Torque all fasteners to specification using values provided in this procedure.
4. For components without specified torque values in this procedure, use OEM specifications from workshop manual.
5. Reconnect steering intermediate shaft ensuring alignment marks match. Torque pinch bolt to specification.
6. Reconnect all brake lines using new copper washers on banjo bolts where applicable. Torque brake line fittings carefully to prevent stripping aluminum components.
7. Refill all fluids that were drained: engine oil, differential oil (rear), power steering fluid. Bleed brake system completely using proper procedure for ABS-equipped vehicles.
8. Reinstall wheels and torque lug nuts to specification in star pattern.
9. Lower vehicle to ground and perform final torque on control arm bolts with vehicle weight on suspension (critical for bushing longevity).

Verification

• With vehicle on level ground, verify ride height is equal side-to-side and matches pre-service measurements.
• Perform steering lock-to-lock check (engine running for power steering) and verify no binding or unusual noises.
• Check all fluid levels and inspect for leaks at all disconnected connections. Run engine for 5 minutes and re-check.
• Test brake pedal feel—should be firm with no excessive travel. If pedal is soft, re-bleed brake system.
• Road test vehicle at low speed (under 25 mph) in safe area and verify straight-line tracking, proper steering return, and absence of suspension noises.
• Four-wheel alignment is mandatory after subframe replacement. Schedule professional alignment service immediately—do not drive vehicle at highway speeds until aligned.
• After 50-100 miles of driving, re-torque all subframe mounting bolts and suspension fasteners to specification to account for settling.

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