Power Steering Pump 44310-BZ080 for Toyota Avanza Yaris

Power steering pump 44310-BZ080, also listed as 44310BZ080 and 44310-BZ070, for the Toyota Avanza F60 built from 2002 to 2011 with the 1.3 and 1.5 petrol engines, and for the Daihatsu Xenia 1.3, which is the same vehicle sold under the Daihatsu badge.

The pump is a belt driven vane type unit mounted on the engine, fed from a remote reservoir and feeding the steering rack through a pressure line. Inside the aluminium housing a rotor carries a set of sliding vanes that sweep an eccentric ring, so the volume between two vanes changes as the rotor turns and fluid is pushed out under pressure. A flow control valve on the outlet keeps delivery roughly constant as engine speed rises, and a pressure relief valve opens if the driver holds the wheel against the stop, which protects the pump and the seals in the rack.

Because the Avanza and the Xenia share the whole front end, the steering hydraulics are identical between the two, and one pump covers both. Worth knowing when a customer asks: the 1.0 litre Xenia variants were sold without power steering at all, so there is nothing to replace on those cars. The 1.3 is the version this pump fits.

How these pumps fail. The first symptom is usually a groan or whine that rises and falls with engine speed and gets louder when the wheel is turned at a standstill. A pump that whines only when cold and quietens once warm is often just aerated fluid from a low reservoir or a leaking suction hose, so check the level and the hose clamps before condemning the pump. Real internal wear shows up as heavy steering at idle that improves as soon as the revs rise, because the pump can no longer make pressure at low speed. Fluid that has turned dark grey or black, or that foams and overflows the reservoir cap, points to a pump that is grinding itself up and sending debris into the rack.

Fitting notes. Suck the reservoir dry rather than draining it onto the belt, disconnect the pressure line with a flare nut wrench so the fitting is not rounded, and cap both open ends immediately because dirt in the rack is far more expensive than a new pump. Clean the mounting face, fit the new pump with a fresh O-ring on the pressure port, and torque the bolts evenly. Fill with the specified fluid, then bleed the system properly: raise the front axle, turn the wheel lock to lock slowly with the engine idling and the reservoir cap off, topping up as the level drops, and repeat until no bubbles appear and the pump is quiet. Do not hold the wheel on the stop for more than a couple of seconds during bleeding.

Supplied as a complete pump assembly, pressure tested before packing. Twelve month warranty.