Rebuilt Power Steering Pump Price: From JPY 55,000

Prices may fluctuate due to the rising cost of parts.

For reference, the brand-new genuine part costs approximately JPY 123,000 to 138,000.
We also supply brand-new parts and overhaul kits.
If you are interested in new parts or overhaul kits, please feel free to contact us. We will check the current price and availability for you.

Replacing the entire pump can be a quicker solution in some cases.
However, some users may prefer to disassemble, clean, and rebuild the existing unit — depending on the condition and repair approach.

For such needs, we also offer Customizable Overhaul Kits with the necessary parts.

The images on this page are of actual rebuilt parts supplied by Auto Parts Box Japan.

The Stress Drifting Puts on the Power Steering Pump

1. Frequent and Rapid Steering Input
   • Frequent “lock-to-lock” movements:
     During drifting, the driver repeatedly and rapidly turns the steering wheel from full left to full right—something rarely done in normal driving.
     This causes the power steering pump to operate near its maximum pressure almost constantly, putting a significant strain on the system.
   • Quick countersteering:
     Countersteering (turning the wheel in the opposite direction of the vehicle’s slide) must be performed quickly and precisely.
     These sudden and aggressive steering inputs create sharp, momentary loads on both the power steering pump and the rack.
2. High Tire Friction and Steering Kickback
   • Lateral tire slip:
     During a drift, the tires slide sideways across the road surface, generating intense friction.
     This friction translates into strong kickback forces that are fed back into the steering system.
   • Increased resistance:
     In normal driving, most friction occurs in the direction of travel. In drifting, however, the tires are angled and sliding sideways, which increases resistance against the steering axis.
     The power steering system must overcome this resistance, requiring higher hydraulic pressure.
3. Fluid Overheating and Degradation
   • Pump overheating:
     Constant high-output operation and increased resistance cause the power steering fluid temperature to rise rapidly.
   • Fluid foaming (cavitation):
     As fluid temperature increases, viscosity decreases. Under intense pump operation, this can cause cavitation—where air bubbles form in the fluid.
     Since air is compressible, this leads to unstable hydraulic pressure and, at times, temporary loss of steering assist.
   • Fluid overflow:
     Foaming increases the volume of the fluid, which may cause it to overflow from the reservoir tank.
     If the fluid contacts hot engine components, it could be dangerous.
     In addition, a loss of fluid can lead to pump starvation or even pump failure due to overheating.

Rotary Engines and the “Onigiri” Rotor

Unlike regular engines where pistons move up and down inside cylinders to generate power, a rotary engine doesn’t use pistons at all.

The Moving “Onigiri” That Powers the Engine!
At the heart of a rotary engine is a triangular-shaped part that looks surprisingly like a Japanese rice ball, or onigiri. This part is called the rotor.

As this onigiri-shaped rotor spins around inside a specially shaped housing, it burns fuel and generates power.

Why is it Called an “Onigiri”?
The nickname comes from its rounded triangular shape, which resembles onigiri — a traditional Japanese rice ball, usually hand-shaped into a triangle and wrapped in seaweed. It’s a beloved snack in Japan, and car fans affectionately use the term to describe the rotor’s familiar shape.

Thanks to this unique design, rotary engines are incredibly compact yet capable of producing impressive power.