Power steering pump. Porsche 986 Boxster / 987 Boxster / 987C Cayman / 996 / 997

Power steering pump. 
The power steering pump converts engine power into hydraulic pressure for the power assisted steering system, enabling smooth, effortless steering and consistent responsiveness. Built to OE specification.

Fits:
  * M657 - for cars with power assisted steering
Porsche 986 Boxster 1997 - 2004
Porsche 987.1 Boxster 2005 - 2008
Porsche 987C.1 Cayman 2005 - 2008
Porsche 996 Carrera 1998 - 2005
Porsche 997.1 Carrera 2005 - 2008

Diagram ref no 9

• Position on Vehicle: Mounted within the engine bay on the front accessory drive system, connected to the power-steering fluid reservoir and rack/column assembly.

•  Cross-Reference / Alternative Numbers: OEM number 996 314 050 03 (sometimes referenced as 99631405003); supersedes part number 996 314 050 02.

•  Applications: Replacement whenever the original pump shows symptoms such as whining noise, fluid leakage, reduced steering assist or erratic steering feel - helping to restore proper steering function and driver confidence.

The power steering pump is central to the assistive steering system, providing hydraulic pressure needed for effortless steering and precise control. When the pump begins to fail - through internal wear, leakage, or loss of hydraulic efficiency - drivers may experience noisy operation, heavier steering effort, or inconsistent responsiveness. Replacing it with a fresh unit restores hydraulic integrity, ensures consistent steering feel and prevents further wear on associated steering components.

When and why to replace:
• Steering becomes notably heavier or varied in effort than expected.
• Noticeable whining or groaning noise when steering, especially at low speeds.
• Visible fluid leakage from the pump or associated lines/fittings.
• After other steering components (rack, links) have been serviced - a failing pump would compromise the rebuild.
• On high-mileage vehicles where original pump has been in service long and may be approaching end-of-life.


Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99631405003

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