Control arm (Slim type) 'Coffin Arm'. Porsche 986 Boxster and 996  ❭  99634105320

Wishbone control arm with lower ball joint
The Porsche Genuine OE Control Arm ‘Coffin Arm’ (Slim Type) is an original factory lower suspension control arm / wishbone assembly designed for the Porsche 986 Boxster and Porsche 996 generation 911 models. Commonly known as the “Coffin Arm” due to its distinctive shape, this suspension arm forms a key part of the multi-link suspension system used on water-cooled Porsche models. The slim-type version is fitted with an integrated lower ball joint and suspension bushes for precise suspension geometry and handling performance.

Fits:
Porsche 986 Boxster 1997 - 2004 FRONT or REAR
Porsche 996 C2 / C4 / C4S 1998 - 2004 FRONT or REAR
Porsche 996 Turbo 2000 - 2005 FRONT or REAR (non adjustable)
Porsche 996 GT3 1999 - 2002 MKI REAR
Porsche 996 GT3 2003 - 2005 MKII REAR (non adjustable)

Please note this arm is not adjustable (not motorsport - M004 option)

Diagram ref no 21

The coffin arm controls wheel movement and suspension geometry while allowing smooth suspension articulation during steering, braking, and cornering.

It connects the wheel carrier to the chassis/subframe and works together with the shock absorber and track control arms to maintain:
• Precise steering response
• Stable wheel alignment
• Ride comfort
•  Porsche handling characteristics

The integrated bushes absorb vibration and road harshness, while the lower ball joint allows controlled movement of the suspension assembly.

Functions & Technical Role
•  Suspension geometry control: Maintains correct wheel alignment and movement
•  Integrated lower ball joint: Allows smooth articulation during suspension travel
•  Vibration damping: Suspension bushes reduce harshness and road vibration
•  Handling stability: Supports accurate steering and chassis balance0
•  OEM engineering: Manufactured to Porsche factory specifications for exact fitment and durability

Fitment / Position on Car
•   Fitting position: Front or rear axle depending on model/application
•   Side: Left = Right
•   System: Suspension and steering geometry control

Typically installed as: Front lower control arm or Rear lower control arm (GT/Turbo applications)

The coffin arm plays a major role in steering precision, suspension stability, and tyre wear control. Worn bushes or ball joints can negatively affect handling, ride comfort, and alignment accuracy.

When to replace
•  Knocking or clunking from suspension
•  Excessive play in the ball joint or bushes
•  Uneven tyre wear or poor wheel alignment
•  Vague steering or unstable handling
•  During suspension rebuild or overhaul

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99634105320

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