Front Suspension Refresh Guide
Decision framework for a comprehensive front suspension refresh on the SC430. This guide covers what to inspect, what to replace, sourcing decisions, and estimated costs.
Step 1: Diagnose before buying parts
Check struts first. Blown front struts produce nearly identical symptoms to worn control arm bushings — wandering, vague steering, poor ride quality. If the struts are leaking oil or have 100,000+ km on them, replace those first and re-evaluate before ordering control arm parts [Probable].
Diagnostic checklist
- Struts — look for oil leaking down the strut body. Bounce test: push down on the front corner and release — it should return to rest in one bounce, not keep oscillating.
- Caster arm bushings — visual inspection for cracked, bulging, or collapsed rubber. See Caster Arm Bushing Degradation.
- Upper control arm ball joints — jack up, grab wheel at 12/6 o’clock, check for play. See Upper Control Arm Ball Joint Wear.
- Lower ball joints — similar check, isolate upper vs lower.
- Tyre wear pattern — inside-edge wear suggests camber issue. See Factory Camber Tyre Wear.
- Alignment history — if alignment won’t hold, bushings are likely degraded.
Step 2: Decide what to replace
Minimum refresh (addressing specific symptoms)
- Caster arm bushings or full caster arms — if bump steer / wandering
- Upper control arms — if ball joint play detected
- Lower ball joints — if lower joint play detected
Comprehensive refresh (the “while you’re in there” approach)
If the car has 150,000+ km and you’re replacing caster arm bushings, strongly consider doing everything at once. You’re already pulling the suspension apart, and the labour overlap is significant [Probable].
Full front suspension parts list (both sides):
| Component | OEM Part Numbers | Confidence |
|---|---|---|
| Upper control arms (pair) | 48610-39085 Front Upper Control Arm Right + 48630-39055 Front Upper Control Arm Left | [Verified] |
| Lower arms #1 (pair) | 48068-30300 Front Lower Arm Right + 48069-30300 Front Lower Arm Left | [Verified] |
| Caster arms (pair) | 48660-24020 Caster Arm Right + 48670-24020 Caster Arm Left | [Verified] |
| Lower ball joints (pair) | 43330-39535 Front Lower Ball Joint Right + 43340-39415 Front Lower Ball Joint Left | [Verified] |
Step 3: OEM vs aftermarket
Cost comparison — full set, both sides (April 2026)
| Component | OEM (AUD) | Quality aftermarket (AUD) | Economy aftermarket (AUD) |
|---|---|---|---|
| Upper control arms x2 | ~$958 | ~$256 (Moog) | ~$80 (Ultra-Power) |
| Lower arms #1 x2 | ~$496 | ~$138 (Mevotech/Moog) | ~$138 (Ultra-Power) |
| Caster arms x2 | ~$370 | ~$370 (OEM — limited aftermarket for full arm) | — |
| Lower ball joints x2 | ~$234 | ~$100 (Moog K500101) | — |
| Total | ~$2,060 | ~$730 (quality mix) | Lower possible |
All prices approximate, April 2026. AUD unless noted. [Probable]
Decision guidance
- OEM — peace of mind, exact fit, longer expected life. Worth it if you plan to keep the car long-term.
- Quality aftermarket (Moog, TRW, Delphi) — significant savings, acceptable quality for most owners. Moog is the most commonly recommended on forums [Probable].
- Economy (Ultra-Power, unbranded) — cheapest up front but quality is unknown. Fine for a car you’re flipping, risky for a car you’re keeping [Reported].
- Adjustable UCAs — if you also want to fix the Factory Camber Tyre Wear issue, fit adjustable UCAs (SPC 72270 or Mevotech CMS861207) instead of standard replacements. More expensive but solves two problems at once.
Poly vs rubber caster arm bushings
If replacing bushings rather than full caster arms:
- OEM rubber — original ride quality, will degrade again in 80K–100K miles
- Polyurethane (FIGS Engineering G1149, SuperPro SPF4186K) — lasts longer, slightly firmer ride. Preferred by enthusiast owners [Probable]
Step 4: Torque specifications
These torque specs are from forum DIY threads, not from the official Toyota/Lexus service manual [Probable]. Have your mechanic verify against factory specs if available.
| Fastener | Torque | Confidence |
|---|---|---|
| UCA mounting bolts | 121 ft-lbs (164 Nm) | [Probable] |
| UCA ball joint nut | 80 ft-lbs (108 Nm) | [Probable] |
| Lower arm #1 to support arm | 122 ft-lbs (165 Nm) | [Probable] |
| Lower ball joint to knuckle | 83 ft-lbs (113 Nm) | [Probable] |
| Shock absorber bottom bolt | 136 ft-lbs (184 Nm) | [Probable] |
Step 5: DIY feasibility
Difficulty: Moderate to advanced
- Time estimate: 4–6 hours for both sides (control arms and ball joints). Full weekend for comprehensive refresh including struts [Probable].
- Skills needed: Comfortable with suspension work, torque wrenches, jack stands. Ball joint separator or pickle fork required.
- Special tools:
- Ball joint separator / pickle fork
- Hydraulic press (if pressing caster arm bushings rather than replacing full arms)
- Torque wrench (ft-lbs range above)
- Spring compressor (if doing struts)
- Breaker bar — these bolts are torqued tight and may be corroded
- Penetrating oil (PB Blaster or similar) — apply the day before
Tips
- Paint lower ball joints with VHT epoxy before installation to prevent rust [Reported]
- Replace in pairs — always do both sides. One new arm and one worn arm creates asymmetric handling.
- Mark cam bolts before removal — photograph their positions so the alignment shop has a starting reference.
- Alignment is mandatory after any control arm or ball joint replacement. Budget for this.
Step 6: Post-install alignment
Alignment is mandatory after any front suspension component replacement. Without it, you’ll chew through tyres and the car will handle unpredictably.
If you’ve fitted adjustable UCAs, bring the preferred settings (see Factory Camber Tyre Wear):
| Parameter | Preferred range | Confidence |
|---|---|---|
| Front camber | -0.5 to -0.85 degrees | [Probable] |
| Front toe | +0.05 degrees | [Probable] |
| Rear camber | -1.0 to -1.25 degrees | [Probable] |
| Rear toe | +0.15 degrees | [Probable] |
Print these and hand them to the alignment tech. Not all shops are familiar with SC430 preferred specs.
Sources
Research data from forum threads, OEM parts listings, and owner reports (April 2026 ingest).
Related
- Front Suspension — system overview
- Caster Arm Bushing Degradation — most common failure trigger for a refresh
- Upper Control Arm Ball Joint Wear — second most common failure
- Factory Camber Tyre Wear — camber correction during refresh
- FIGS Engineering — specialist suspension parts supplier