What is the spiral spring shock absorber pad at the rear of the car?
The rear suspension spring buffer pad (often referred to as "buffer gel", "shock absorption gel", or "spring limit block") is a highly elastic non-metallic component installed on the contact surfaces at both ends of the rear suspension spring (between the vehicle longitudinal beam/top beam and the lower control arm). Its main function is to provide flexible limitation and shock absorption at the end of the spring compression stroke, avoiding hard collisions between metal parts.
Key Characteristics
Material: Mostly high-density natural rubber, polyurethane (modern models tend to use porous polyurethane with large deformation and good non-linearity), with a Shore hardness typically ranging from 55 to 70A.
Structure: Open circular shape, with spring-matching grooves/limit rings. Some original designs include a metal frame or replaceable buffer layers (such as the "base + detachable buffer pad" combination in the patent).
Function Positioning:
Absorbing high-frequency vibrations and shock at the end of compression, reducing "thumping" abnormal sounds;
Delaying the fatigue of the spring/absorber, preventing damage to components due to excessive compression;
Improving driving comfort, but not participating in active damping (not a damping element), nor bearing the main load.
Life and Failure Signals: Normal cycle is approximately 3–5 years; after aging, it manifests as disappearance of bumping rumbling, hardening of the chassis, and easy shaking of items in the trunk.
Notes for Attention
Spring washer for bolts: The latter is a metal anti-loosening component (open spiral shape), used for threaded connections, with limited anti-loosening capability and not suitable for suspension damping scenarios.
Installation requirements: The vehicle body needs to be lifted to release the spring tension, the contact surfaces need to be cleaned, and it should be matched according to the model (A–F, etc.) to avoid uneven force distribution due to skewing.
Some high-end/patented designs (such as Jiangling-related patents) integrate the damping pad into the angle-adjustable pad assembly to optimize the uniformity of spring force under inclined installation.
Note: If there is abnormal noise or harsh suspension, prioritize checking if the damping pad is aged, cracked, or missing rather than directly replacing the spring/damper.
The core function of the rear suspension spring damping pad (damping gel/limiting block): Provides a "flexible transition" under the extreme compression condition of the suspension, absorbing impact energy to prevent "clunking" noise and wear of the spring seat/tower top.
Protection of suspension components: Reduces direct friction between the spring end ring and the metal seat, delays fatigue; also prevents the shock absorber piston rod from being damaged due to excessive compression (especially after aging and cracking, it is prone to adhering and burning out the sealing component).
Improvement of NVH performance: Isolates high-frequency vibration transmission, improves chassis quietness and driving smoothness; factory-matched parts have an implicit contribution to handling stability (such as suppressing abnormal rebound divergence).
Key points
Non-daily load-bearing: It basically has no effect during normal road driving, excessive installation or inferior products may make the suspension harder and disrupt the original factory calibration balance.
No substantial increase in load-bearing capacity: Some products claim to "raise the vehicle body by 0.2–0.3 cm", but they cannot enhance the spring stiffness or load capacity, only compensate for slight weakness.
Aging risk: Rubber/urethane materials tend to crack and powderize over time, regular inspection and replacement are required; absence or failure will lead to increased chassis noise and accelerated component wear.
Position characteristics: Usually installed at the upper and lower ends of the spiral spring (not in the middle of the pitch), working in coordination with the top rubber and shock absorber; itself does not have an independent damping function (damping relies on hydraulic shock absorbers).
Note: The original factory design already includes matching damping pads, non-essential modifications and additions are not recommended; if there is abnormal noise or suspension abnormalities, prioritize checking if the original factory damping pad is aged or deformed.
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