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Porsche // Boxster 986/987/981 (1997-2016) // Boxster 987 MKII 2.9L 2009-12
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- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 996 TURBO 2000-05
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MKII Carrera C4 3.6L 2009-12
- Porsche 997 MKII Carrera C4S 3.8L 2009-12
- Porsche 997 MKII GT3 / GT3 RS 2010-11
- Porsche 997 MKII Turbo 2010-13
OE Match shock absorber strut bellows for selected Porsche 996 and 997 applications, supplied as two Front protective covers. These bellows shield the damper rods from dirt and debris.
Fits
- Porsche 996 C4 / C4S 1997-05
- Porsche 996 Turbo 1999-05
- Porsche 997 C4 / C4S 2005-12 (MKI & MKII)
- Porsche 997 Turbo 2007-12 (MKI & MKII)
- Porsche 997 GT3 2010>>
Check fitment for your specific vehicle (model, year, engine) before ordering.
What This Product Does
A strut bellows provides a flexible protective covering around the exposed damper rod, accommodating suspension movement while limiting contamination. It is a protective component rather than a shock absorber, mounting bearing or bump stop.
Functions
- Shields the damper rod against road dirt and debris.
- Maintains protective coverage as the suspension moves.
Technical Details
- Supplied quantity: two bellows.
- Position specified for this set: Front.
- Component reference: 99634350901.
- Brand: OE Match.
- GT3 restriction: use only with shock absorber 997.333.051.99; the supplied diagram records the application note as 10-.
Symptoms of Fault
- Visible cracks, splits or missing sections in an existing cover.
- A displaced bellows leaving the damper rod exposed.
- Rattling associated with a loose or damaged dust cover; inspect adjacent hardware before attributing the noise to the bellows.
Why Replacement Matters
Renewing damaged bellows restores the protective covering around the damper rod. During damper servicing, inspect both covers alongside the mounts, bearings and bump stops rather than automatically reusing deteriorated components. A new cover will not correct leakage or internal damper wear.
FAQs
Are two bellows included?
Yes, this set contains two protective bellows.
Should these be checked when changing dampers?
Yes. Examine the covers for damage and confirm that they fit the replacement dampers.
Does the GT3 application have a restriction?
Yes. The supplied diagram specifies use only together with shock absorber 997.333.051.99.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99634350901
The product you are viewing cross references to these numbers
This kit is comprised of the following items:
- 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 C2 3.6L 09/01-2005
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MKII Carrera C2 3.6L 2009-12
- Porsche 997 MKII Carrera C2S 3.8L 2009-12
- 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
FRONT
Fits:
Porsche 996 C2 / C2S 1998 - 2005
Porsche 997 C2 / C2S MKI 2005 - 2008
Porsche 997 C2 / C2S MKII 2009 - 2010
Porsche 986 Boxster 1997 - 2004
Porsche 987.1 Boxster 2005 - 2008
Porsche 987.2 Boxster 2009 - 2012
Porsche 987C.1 Cayman 2005 - 2008
Porsche 987C.2 Cayman 2009 - 2012
Diagram ref no 11
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99634351505
The product you are viewing cross references to these numbers
- 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 C2 3.6L 09/01-2005
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MKII Carrera C2 3.6L 2009-12
- Porsche 997 MKII Carrera C4 3.6L 2009-12
- Porsche 997 MKII Carrera C2S 3.8L 2009-12
- 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
Front.
Fits:
Porsche 996 C2 1998-05
Porsche 997 C2 /C2S MKI 2005-08
Porsche 997 C2 /C2S MKII 2009-10
Porsche 986 Boxster 1997-04
Porsche 987 Boxster 2005>>
Porsche 987C Cayman 2005>>
Options:
- 3.0 mm
- 6.5 mm
Please select below
Diagram ref no 5
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
9963435110
The product you are viewing cross references to these numbers
- 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
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.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99634330102
The product you are viewing cross references to these numbers
- 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 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche 997 MKII Carrera C2 3.6L 2009-12
- Porsche 997 MKII Carrera C2S 3.8L 2009-12
- 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
Fits:
Porsche 996 C2 / C4 / C4S 1998-05
Porsche 997 MKI C2 / C2S 2005-08
Porsche 997 MKII C2 / C2S 2009-10
Porsche 986 Boxster 1997-04
Porsche 987 Boxster 2005-08
Porsche 987 MKII Boxster 2009>>
Porsche 987C Cayman 2005-08
Porsche 987C MKII Cayman 2009>>
Click 'Zoom in' for large parts diagram.
Diagram ref no 4
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99634351701
The product you are viewing cross references to these numbers