helper spring Genuine Porsche part 99634330102

Shock Absorber Additional Spring - Front
Sold each - 2 required per car

Maintain the performance, comfort and protection of your Porsche suspension system with this OE Match Shock Absorber Additional Spring. Commonly referred to as a bump stop or auxiliary spring, this component is fitted to the shock absorber assembly and plays an important role in controlling suspension movement during extreme compression.

Fits:

• Porsche Boxster 986 2.5L 1997-99
• Porsche Boxster 986 2.7L 1999-02
• Porsche Boxster S 986 3.2L 1999-02
• Porsche Boxster 986 2.7L 2003-04
• Porsche Boxster S 986 3.2L 2003-04
• Porsche Boxster 987 2.7L 2005-08/08
• Porsche Boxster 987 S 3.2/3.4L 2005-08/08
• Porsche Boxster 987 MKII 2.9L 2009-12
• Porsche Boxster S 987 MKII 3.4L 2009-12
• Porsche 996 C2 3.4L 1997-08/01
• Porsche 996 C4 3.4L 1997-08/01
• Porsche 996 C2 3.6L 09/01-2005
• Porsche 996 C4 3.6L 09/01-2005
• Porsche 996 C4S 3.6L 09/01-2005
• Porsche 996 TURBO 2000-05
• Porsche Cayman 2.7L 987C 2006-08
• Porsche Cayman S 3.4L 987C 2005-08
• Porsche Cayman 2.9L 987C MKII 2009-12
• Porsche Cayman S / R 3.4L 987C MKII 2009-12

Diagram ref no 9

Designed for use on Porsche 986 Boxster, 987 Boxster and Cayman, and 996 Carrera models, the additional spring helps absorb impacts when the suspension approaches the end of its travel. This protects the shock absorber, suspension components and chassis from excessive loads while maintaining ride quality and vehicle control.

Over time, the additional spring can deteriorate due to age, compression cycles, road contamination and exposure to heat and moisture. Replacing worn bump stops is an important part of any suspension overhaul and helps restore factory suspension performance.

What Does the Shock Absorber Additional Spring Do?

The additional spring acts as a progressive cushion during suspension compression.

Its primary functions include:

• Absorbing extreme suspension loads
• Preventing metal-to-metal contact
• Protecting shock absorbers
• Protecting suspension components
• Improving ride comfort
• Maintaining suspension control
• Supporting chassis protection
• Reducing impact harshness

It forms an important part of the suspension system, especially during hard cornering, heavy braking or driving over uneven road surfaces.

Why Do Additional Springs Fail?

Additional springs are constantly subjected to compression, environmental exposure and ageing.

Common causes of failure include:

• Age-related foam deterioration
• Repeated compression cycles
• Road dirt contamination
• Water ingress
• Heat exposure
• UV degradation
• Physical damage during suspension servicing
• General wear and tear

Over time the material can crack, crumble, compress permanently or disintegrate completely.

Symptoms of a Worn Additional Spring

Common signs of failure include:

• Visible cracking or splitting
• Missing sections of foam material
• Deteriorated or crumbling bump stops
• Increased suspension harshness
• Knocking noises over bumps
• Reduced ride quality
• Suspension bottoming out
• Uneven suspension behaviour

Many worn bump stops are only discovered during shock absorber replacement or suspension inspections.

When Should the Additional Spring Be Replaced?

Replacement is recommended when:

• Installing new shock absorbers
• Carrying out suspension refurbishment
• The spring shows visible deterioration
• Suspension noises are present
• Ride quality has deteriorated
• The vehicle has covered high mileage
• Performing preventative maintenance
• Completing a Porsche restoration project

Most suspension specialists recommend replacing bump stops whenever dampers are renewed.

Why Replacement Matters

A worn or damaged additional spring can reduce suspension protection and negatively affect ride quality.

Benefits of replacement include:

• Improved suspension performance
• Better ride comfort
• Enhanced shock absorber protection
• Reduced suspension noise
• Improved vehicle control
• Prevention of suspension damage
• Restoration of factory ride characteristics
• Improved long-term reliability

Replacing this inexpensive component during suspension maintenance can significantly improve overall suspension performance.