Bounce the rear of the car by stepping on the bumper -- if only the tires move, not the suspension, or it is VERY hard, you need new accumulators. Not a bad fix -- get the new accumulators and a quart of hydraulic fluid (use ONLY the MB stuff, anything else will cause you much more expensive repairs....).

Put the rear of the car up on jack stands for acesses, then clean the connections for the hydraulic lines, removing lines, remove accumulators, catch the dripping oil, install new accumulators, re-install hydraulic lines, and refill the fluid reservior.

On the W123, the accumulators are under the rear passenger floor, accessable from under the car.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!