What causes the shock absorber to have resistance when compressed but not rebound?
4 Answers
The reasons why a shock absorber has resistance when compressed but does not rebound are as follows: Since the rebound force of the shock absorber is provided by the shock-absorbing spring absorbing road vibrations and impacts, once the shock-absorbing spring is damaged, it will greatly affect the rebound force of the shock absorber. Below is relevant information about shock absorbers: Working principle: The working principle is that when the frame (or body) and axle experience relative movement due to vibration, the piston inside the shock absorber moves up and down, causing the oil in the shock absorber chamber to repeatedly flow from one chamber to another through different pores. Purpose: To accelerate the attenuation of frame and body vibrations and improve the vehicle's ride smoothness (comfort), most vehicles' suspension systems are equipped with shock absorbers.
I've been in auto repair for over a decade, and when I encounter shock absorbers that resist compression but fail to rebound, it's usually a classic sign of either leaked fluid or internal piston seizure. Shock absorbers rely on hydraulic pressure to dampen vibrations – once the fluid leaks out, the piston gets stuck in the compressed position and can't spring back. In some older vehicles, prolonged valve wear can also cause them to lock up. The check is straightforward: look for oil stains or rust marks on the exterior of the shock absorber, and press down on the spring area near the tire to test. Don't ignore this issue – driving without proper damping feels like having no suspension at all, leading to severe bumpiness, handling difficulties, and significantly increased skid risks during turns. I recommend stopping driving immediately and getting professional replacement. For routine maintenance, regularly checking for balanced tire pressure can help delay aging.
I had this exact experience with my car before. After running for just over six years, one day I noticed the shock absorber felt stiff when pressed down and wouldn't bounce back when released, just like a dead snake. This was mostly because the oil inside the shock absorber had leaked out completely, likely due to the aging of the sealing rings causing the oil to seep away. Sometimes, it's because the piston rod is bent or jammed with accumulated dust, getting stuck when force is applied. I first checked the car's balance myself: the car wobbled noticeably on flat roads, especially when going over speed bumps, making constant thumping noises. Don't try to save money by making do with it—send it to the repair shop right away. The mechanic diagnosed it in no time, replaced the part, and it was back to normal. A reminder to everyone: when washing your car regularly, take a moment to inspect the undercarriage. Any shortage of fluids or damage can be spotted early, preventing breakdowns or accidents on the road.
The shock absorber has resistance when compressed but does not rebound, and the common reasons are as follows: First, oil leakage—without oil, it cannot rebound with force; second, internal valve blockage, such as spring rust or debris clogging; third, piston seal failure or deformation, with the piston rod misaligned and stuck in the middle position; fourth, external impact damage, such as hitting a large pothole that bends components. The inspection method is simple: check for oil leakage or dents on the outside of the shock absorber. For prevention, drive less on bumpy roads and perform regular maintenance. Address issues promptly to avoid worsened handling and accelerated tire wear.
