Buy Lexus SC430 Power Steering Pumps

• Fits every SC 430 model year (2002-2010) with the 3UZ-FE V-8 engine. (parts.lexusofriverside.com)
• Factory part number most often stamped on the casting is 44320-30570. (parts.belllexusnorthscottsdale.com)
• The pump is belt-driven; it shares a single serpentine belt with the alternator and A/C compressor. (mr2.com)
• Normal relief-valve pressure is about 1,100-1,300 psi, similar to most Toyota V-8 pumps. (lextreme.com, turnonesteering.com)
• Lexus specifies Dexron III automatic-transmission fluid (not generic Òpower-steering fluidÓ). See the official Lexus support note here.

Inside the aluminum housing is a slotted rotor that spins off-center inside a crescent-shaped chamber. Tiny vanes ride the slots and sweep Dexron III ATF from the inlet to the outlet, building high pressure for the steering rack. When you turn the wheel, a flow-control valve in the pump reacts, sending the right amount of assist so the wheel never feels jumpy or heavy. (turnonesteering.com)

• Whine or groan: Air bubbles or worn bearings make the pump noisy, most obvious at idle or full lock. (clublexus.com)
• Hard steering: Low fluid, a clogged screen, or an internal vane failure can starve the rack. (Reddit)
• Red fluid on alternator: A leaky front seal often drips straight onto the alternator and may kill it-a well-known Toyota V-8 issue. (lextreme.com)
• Foamy reservoir or burnt smell: Overheating fluid loses lubrication and turns brown. (mirrors.arcadecontrols.com)

Age, heat, and dirty fluid wear the vane tips and shaft seal. On the SC 430, short fluid hoses let engine heat cook the pump faster than on sedans. Running the reservoir low even once can scar the pump's internal surfaces. Persistent leaks are common around the O-rings that seal the pressure-control valve and hose banjo bolt. (Lexus Owners Club of North America)

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1. Relieve belt tension. Slide a 14 mm wrench on the tensioner and rotate clockwise. Remove the belt. (YouTube)
2. Drain fluid. Pinch the return hose and pull it off the reservoir; aim into a catch can.
3. Remove hoses. Crack the 17 mm banjo bolt; catch any washers. Mark hose routing.
4. Unbolt pump (three 12 mm bolts) and lift out. Support the alternator so it doesn't take weight. (Lexus Owners Club of North America)
5. Swap pulley. Use an impact driver or jam the old pulley with a strap wrench; torque the nut to 32 ft-lb.
6. Install new pump, new O-rings, and fresh washers. Tighten bolts to 29 ft-lb and banjo bolt to 36 ft-lb.
7. Bleed system. Fill reservoir, turn wheel lock-to-lock 20 times with engine off, then start engine and repeat until bubbles stop. (YouTube)

• Add a $5 universal fluid filter in the low-pressure return line to catch debris. (turnonesteering.com)
• A UV dye kit helps find tiny leaks when the pump spills only under load. (Reddit)
• Many owners flush with a turkey baster every oil change; clean fluid equals long pump life. (Reddit)
• A small fluid drip shield, borrowed from later Lexus LS models, snaps between pump and alternator to protect electrical parts. (RepairPal.com)

Enthusiasts have swapped in the LS 430 pump (part # 44310-50070). It fits the bracket but uses a slightly smaller pulley, so you must install a marginally shorter serpentine belt to keep proper tension. (Facebook)

Power-steering fluid is combustible. Keep rags away from headers and dispose of old ATF at any auto-parts store's recycling tank. Wipe spills-the pump sits high, and drips can reach the catalytic converter and smoke. (turnonesteering.com)

Q: What fluid should I top up with?
A: Use Dexron II or Dexron III ATF-the same red fluid many transmissions use. Plain Òpower-steering fluidÓ is not recommended for this Lexus. (support.lexus.com)

Q: Why did my alternator die right after the pump started leaking?
A: The pump sits directly above the alternator. Leaks run straight down, soaking the alternator windings and shorting them out. Fix leaks quickly or shield the alternator. (lextreme.com)

Q: How long can I drive with a whining pump?
A: A short trip home is usually fine, but running low on fluid can overheat and score the pump, leading to sudden steering loss. Top up and plan a repair soon. (Reddit)

Q: Do I have to remove the radiator fan?
A: No, there's enough room to slide the pump out once the serpentine belt and hoses are off, saving time. (YouTube)

Q: Can I rebuild the pump myself?
A: Yes. A seal kit costs less than $60, and a detailed photo guide shows every step. (LexLS rebuild tutorial) (mirrors.arcadecontrols.com)

Q: Does higher-mileage fluid cause failure?
A: Dirty fluid raises wear; many owners report pumps lasting 200 k mi when the ATF is flushed every 30 k mi. (Lexus Owners Club)

Q: How tight should the high-pressure hose be?
A: Torque the banjo bolt to 36 ft-lb with fresh copper washers; overtightening can strip the aluminum housing. (mirrors.arcadecontrols.com)

Q: What if the steering feels heavy only when cold?
A: A sticking flow-control valve or thick, old fluid can cause morning stiffness. Flush with fresh Dexron III and test again. (charm.li)

Q: Can the pump pressure be adjusted?
A: The relief-valve spring controls pressure; shimming raises pressure but risks hose bursts. It's best to keep factory specs around 1,200 psi. (lextreme.com)

By knowing the right fluid, torque numbers, and warning signs, you can keep the SC 430's steering light, quiet, and leak-free for years to come.