W124 self leveling suspension.
 

I recently got a 94 E320 wagon and I noticed that the hydraulic oil reservoir is almost empty. I looked at the reservoir and I couldn't find the full mark on it. Is it supposed to be filled all the way to the top?

There is a rubber cap that is a press fit into the top of the reservoir. There is a dipstick made into that cap. The level is around 3-4 inches from the top. When full by the dipstick I like to take a sharpie and make a line that allows a quick visual check.

After topping it up I would look for the reason it was so low. If you have a hard ride the air cells have most likely sucked up the fluid. Otherwise look for a leak.

Might want to check the valve above the right rear axle. That's where mine was leaking.

J. M. van Swaay

The 'full' line is about the top of the second 'rib' on the SLS reservoir for a W124.

Its prolly the N2 cells, the diaphrams inside them break and all your fluid will collect in them making the reservoir level very low or empty looking....that is, if you find there are no external leaks. Pretty easy to DIY R&R them with regular tools in the driveway. :)

Thanks for the tips guys, I topped it up and found out that it was leaking from the power steering pump. Replaced the return line and the copper washer on the banjo fitting. Looks like it helped, but I'm still not sure if the SLS works. I had two people sit in the trunk and the rear was not raising.

You have to give it about 2000 revs at stand still or go for a drive to get it up (so to speak). Can take a while for it to react and painfully slow or not at all at idle.

VERY good point benzme. :)

Here's a good DIY and education on the system. W124s are basically the same set-up.

http://w140repair.com/Replacing_Accumulators.htm

That's funny... When I go to that link I get this:
"
This is somewhat embarrassing, isn’t it?

It seems we can’t find what you’re looking for. Perhaps searching, or one of the links below, can help."


:D

Try this one.

C:cool::cool:L

Thanks