What purpose does the hydraulic fluid reservoir next to the power steering pump serve?

How do I maintain it?

Thanks Again!

glenn

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Its for your self leveling hydraulic rear suspension. You can buy the fluid from the dealer or online. I do not know the change interval, but I changed mine when I got my wagon.

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68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

It takes a special fluid. Febi makes it for much cheaper than what you pay at the dealership. SLS = self-leveling system. Keeps the rear body height steady when heavy loads are in the back, so that the ride is still nice and the suspension / tire angles stay correct. It is somewhat complex, uses a control valve to fill / empty pressure chambers at the rear axle to maintain the ride height. Your rear axle has hydraulic struts where most cars have shock absorbers; the struts have only one failure mode: leak. They are very expensive to replace. The pressure chambers (aka nitrogen spheres) are the real wear items, need to replace roughly every 100k miles, they provide the damping action that a shock absorber would provide in "normal" suspension.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Fluid change: What I did was disconnect the return line (which is the line connected to the top of the reservoir) and route that into a drain pan. Start car, let engine pump the old oil out from bottom of the reservoir. When it was very nearly empty, start adding new fluid. When you notice the color of the discharge from the return line change from black to clear (new fluid), shut off the car, re-connect the return line, and top up the reservoir.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Thank You Both for your replies. I would like to try Maxbumpo's replacement procedure. Alas, I do not know what the name of the fluid is nor a part number. Would either of you happen to have that information?

Maxbumpo, you mention Febi. Do they have a part number?

Thanks again!

glenn