I've replaced a fair few shocks/dampers on a variety of vehicles now (most recent being last weekend) and they've all failed in the same way, but all passed the MOT(Controle Technique as I'm in France).
Shock absorbers or dampers function on both compression and rebound, rebound being the particularly important one for safety. The CT/MOT only really tests rebound damping, to my knowledge.
All of the units I've replaced over the past few years have had no or very little compression damping, you could easily push the rams in compared to a new unit, however, they all passed the CT and the cars drove 'OK', though our old Toyota had a tendency to bottom the suspension on hard bumps, which slowly got worse and the Panda would sometimes touch the front bumper to the road on a sharp speedbump or pothole.
Change the dampers and the difference was very noticable, the best description I can give is 'stiffer and smoother'. Stiffer in that there is less body roll when cornering and the car feels more firmly 'planted' to the road. Smoother as in imperfections in the road surface are far less noticable.
All the cars I've worked on have been driven extensively on rough country roads, so they've encountered a lot of bumps at higher speeds than they would in the city, maybe this contributed to the dampers failing on compression first. Nothing was leaking and as I said, all passed their tests.
So, I guess what I'm saying is, if you think your car could be smoother over the bumps, or the handling feels even a little bit off, consider changing the dampers, even if they're 'fine' on the MOT, chances are they're getting a bit tired.
Shock absorbers or dampers function on both compression and rebound, rebound being the particularly important one for safety. The CT/MOT only really tests rebound damping, to my knowledge.
All of the units I've replaced over the past few years have had no or very little compression damping, you could easily push the rams in compared to a new unit, however, they all passed the CT and the cars drove 'OK', though our old Toyota had a tendency to bottom the suspension on hard bumps, which slowly got worse and the Panda would sometimes touch the front bumper to the road on a sharp speedbump or pothole.
Change the dampers and the difference was very noticable, the best description I can give is 'stiffer and smoother'. Stiffer in that there is less body roll when cornering and the car feels more firmly 'planted' to the road. Smoother as in imperfections in the road surface are far less noticable.
All the cars I've worked on have been driven extensively on rough country roads, so they've encountered a lot of bumps at higher speeds than they would in the city, maybe this contributed to the dampers failing on compression first. Nothing was leaking and as I said, all passed their tests.
So, I guess what I'm saying is, if you think your car could be smoother over the bumps, or the handling feels even a little bit off, consider changing the dampers, even if they're 'fine' on the MOT, chances are they're getting a bit tired.
