If your vehicle is showing car bounces excessively after hitting a bump, here are the most likely causes and the parts you'll need to fix each one.
Over time, the internal valves and fluid in shocks and struts degrade, losing their ability to dampen the movement of the coil springs. This is the most common reason a vehicle continues to bounce after hitting a bump.
A sudden failure of the internal seals allows the pressurized gas and hydraulic fluid to escape. This results in a complete loss of dampening on that specific corner of the vehicle.
The rubber mounts and bushings that attach the shocks or struts to the vehicle frame can deteriorate or tear. This allows excess play in the suspension, contributing to a bouncy or clunky ride.
Installing the wrong shocks for the vehicle's weight class, failing to prime twin-tube shocks before installation, or tightening suspension bushings while the vehicle is lifted (causing bushing bind) can lead to improper dampening and excessive bounce.
While springs primarily support the vehicle's weight, a broken or severely fatigued spring alters the suspension geometry and spring rate. This forces the shocks to work outside their intended range, leading to a bouncy and sagging ride.