Question about hydraulic on 560SEL 1989
 

My 560SEL 1989 has a four wheel hydraulic system and an adjustment arm near the light switch. My problem is that when I leave the car for one day or more I see the car goes down; so I have to switch on the car for 5 minutes to take the normal level. What is the problem in this case?

Thank you : ))..

Nothing, that is completely normal. The system needs to repressurise itself after sitting idle for a while.

5 mins to pressurise may be a bit long however.

My SL has SLS on all 4 and it doesn't drop. My 16v has SLS on the back and it does not drop. Are they similar systems to the 560?

I saw this post earlier and I am curious about the cause and solution, in case it ever happens on my SL.

My thoughts are that maybe the levelling control valve is leaking by, allowing oil to flow back to the reservoir.

Yes you may be right, I was thinking more of the 600s which used to go down when off.

Where can I find the levelling control valve? I guess it has at least four valves!
Three inside the engine area and one near the differential. So which one I need to check?

By the way, no one in Kuwait understands how to fix the old hydraulic system. They just guess and the customer pays for nothing but sometimes the guess works : ))..

I understand that you have leveling capability on all 4 wheels. Normally, our USA version will have the leveling feature on the rear only. However you still might want to check this site for a basic pressure test of your hydropneumatic leveling sys. It might help you spot leaks.

http://mb.braingears.com/126_DISC2/program/Chassis/32-530.pdf

Brgds,

BENZSTER

I don't know what your valves would look like, but they would definitely mount between either the upper or lower control arms and mounted to the main structure of the car. They will have an adjustment mechanism connecting them to each other, probably rod ends with a threaded rod in between.

As to diagnosis, flying blind here, but I'd guess you would remove the oil supply line and plug it up, and watch for leakage back out the valve? I really have never done this before, so get some more advice.

EDIT - I would put the car up on blocks under the wheels to do this, so as to simulate it being on the ground. I would nut just get under the car and do this - the car may come down on you if you remove the hose and the valve leaks badly!

I thank all of you guys for your help.

Happy new year : ))..