Shock absorbers ...
How it works:
A piston moves in a cylinder full of oil. The piston has some very tiny holes in it so the oil can pass thru: the piston is hard to move; the thinest the hole, the hardest to move. Some of the holes are equiped with non-return valve: in one way, the piston would move quite easily and in the other since the valves are close back, it will be harder. Some shock absorber are adjustable, basically by rotation that cover/freed some extra hole(s).
Failures:
it happen (thanks to huge pot holes) that some valve get dammaged (not closing anymore): the absorber (partly) lose its damping function.
The seal between piston and cylinder can wear, the holes get worn also (lamination), which also lead to a damping loss. Finally the top seal gets worn and you'd have the oil leaking on the absorber body...
Conclusion:
if you feel the car bouncy or see oil on the shock absorber's body, it's probably time for replacement...
BRs, Bernie
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