Shock absorber additional spring.
The replacement helper spring / bump stop assembly for the rear shock absorber on Porsche 987 Boxster and Cayman vehicles. This bump stop is designed to sit atop or within the rear shock/strut assembly, supporting the suspension’s load under compression, preventing harsh bottoming, and helping maintain ride height and handling balance. Manufactured to match Porsche’s original specification in terms of dimensions and elasticity.

Porsche 987 Boxster 2006 - 2008
Porsche 987 MKII Boxster 2009 - 2012
Porsche 987C Cayman 2005 - 2008
Porsche 987C MKII Cayman 2009 - 2012
Porsche 718C (982C) Cayman 2017>>
Porsche 718 (982) Boxster 2017>>
Diagram ref no 8
• Position on Vehicle: Rear suspension, installed within or adjacent to the shock absorber/strut assembly on the rear axle - acts as secondary support (helper spring) or as bump stop to cushion full compression of the suspension.
• Applications: Ideal when your rear suspension exhibits signs of bottoming, excessive squat under load, or the helper-spring/bump stop is missing, fatigued or deformed - improving ride quality, maintaining correct ride height, and preserving handling performance.
The helper spring / bump stop is a critical yet often overlooked component of the rear suspension system. It steps in under heavier loads, sharp compressions or lowered ride-height scenarios to prevent suspension harsh-bottoming, maintain ride height and preserve handling geometry. When the part is worn or missing, you may experience a harsh “clunk” on full compression, inconsistent ride height, rear suspension instability or accelerated wear of other suspension components. Replacing it restores correct support, prolongs suspension life and ensures your car handles the way it was engineered.
When and why to replace:
• Rear suspension bottoms out prematurely under moderate load or when cornering.
• Noticeable change in ride height, rear sagging or uneven posture under load.
• After replacement of rear shock absorbers or other suspension components where the helper spring/bump stop may have been removed or reused.
• High-mileage vehicle where the original component may have degraded or compressed with age.
• If you have lowered or modified your suspension and want to ensure secondary support matches the rest of the system.
Related reference numbersRelated, superseded, cross reference or alternative numbers for comparison.
98733330100The product you are viewing cross references to these numbers