Shock absorbers are normally replaced only if they are leaking excessively (oil visible on the outside cover) or if they are internally worn to a point that the car no longer rides smoothly and rebounds excessively after hitting a bump. A good general test of shock absorber condition is to bounce the front of the car rapidly. Let go. If the car bounces more than twice (or three times, at the utmost), you can assume the shocks need replacing.
You can also examine the shocks for a bent piston rod, which will bind during travel. These shocks should also be replaced.
REMOVAL & INSTALLATION Except 190D, 190E, 1974-76 230, 240D, 280, 280C, 1975-76 300D, 380SL, 380SLC, 450SL and 450SLC Models
See Figures 1 and 2
- Jack and support the front of the car. Support the lower control arm.
- Loosen the nuts on the upper shock absorber mount. Remove the plate and ring.
- Place the shock absorber vertical to the lower control arm and remove the lower mounting bolts.
- Remove the shock absorber.
- Installation is the reverse of removal. On Bilstein shocks, do not confuse the upper and lower plates.
1974-76 230, 240D, 280, 280C, 1975-75 300D, 380SL, 380SLC, 450SL and 450SLC Models
See Figures 3 through 8
- For removal and installation of shock absorbers, it is best to jack up the front of the car until the weight is off of the wheels and support the car securely on jackstands.
- When removing the shock absorbers, it is also wise to draw a simple diagram of the location of parts such as lock-rings, rubber stops, locknuts, and steel plates, since many shock absorbers require their own peculiar installation of these parts.
- Raise the hood and locate the upper shock absorber mount.
- Support the lower control arm with a jack.
- Unbolt the mount for the shock absorber at the top. On 450SL and 450SLC, remove the coolant expansion tank to allow access to the right front shock absorber.
- Remove the nuts which secure the shock absorber to the lower control arm.
- Push the shock absorber piston rod in, install the stirrup, and remove the shock absorber.
- Remove the stirrup, since this must be installed on replacement shock absorbers.
Most models use both Bilstein and F&S shock absorbers. On Bilstein shock absorbers, never re-use the upper or lower cups.
- Installation is the reverse of removal. Always use new bushings when installing replacement shock absorbers.