I have an '88 W126 300SE with the self leveling rear, and was curious to know if anyone has, or knows how to, adjust the base height.

Thanks

First of all, be carefull...raised load, etc.
The base height is adjusted by a control valve body mounted at the rear of the vehicle, near the differential. There is a threaded rod with eye-lets on both ends that acts as the connection between the valve body and the body of the car itself. By lenghthening or shortening this linkage you will be changing ride height. The longer the rod, the heigher the vehicle will ride. Please be carefull, if your not, the whole ca can sink to a very low height and may squish you! In order to check the final height, you will obviously need to have the engine running to pressurize the system. For more information check the search feature, there is lots of info on these systems.

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Here is what I've found. Apparently, it's not recommended to raise the vehicle by mean of the level control rod.


Note
A prerequisite for correct operation of level control as well as for obtaining good riding comfort and optimal riding characteristics is a vehicle level set according to specifications both in condition ready-for-driving and under load.

In condition ready-for-driving the rear end of the vehicle is carried by the rear springs and the basic pressure in the suspension elements only. The basic pressure is maintained by drain valve in level controller independent of position of lever. If rear end of vehicle is too low in condition ready-for-driving, raising of rear end should never be attempted by adjusting connecting rod of level controller, since in such a case the vehicle level would be continuously regulated at too high a level under load. The result would be poor riding characteristics, oil flow and knocking noises during deflection, as well as an essentially too highly placed ball head when operating a trailer. In addition, under high load as well as during acceleration, the max. pressure in suspension elements limited by level controller, would be attained so that during such driving conditions the opening noise of the pressure relief valve would be constantly heard as a whistling and knocking noise. If the level is too low in ready-for-driving condition, corrections should therefore be made on rear springs

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thats some great information! thanks. i'm only interested in lowering the rear by 10-15mm to compliment some lowered front springs. do you forsee any problems?

I do not know the current state of your vehicle rear height. If it is already at the equilibrium state (ie, only the rear springs support the rear) then you can not lower it anymore. You can find this out by disconnecting the control rod and lower the control valve level to see if the rear of the vehicle falls. You need to be very careful like Antony has said. "Please be carefull, if your not, the whole ca can sink to a very low height and may squish you!"

__________________
1991 420SEL Project Car (Completed and rides beautifully) http://www.peachparts.com/shopforum/showthread.php?t=112321
2000 BMW 740IL
2000 Integra Type R - Track Car - SOLD
2005 S2000 - Track Car
06 C230 Sport
89 560SL

This can be done no problem. I recommend doing the adjustment on an alignment rack, and it wouldn't be a bad idea to check the alignment after you do it. Only thing to watch for is to make sure the geometry of the valve and rod is going to be OK. Also never try to move the part of the linkage which is bolted to the rear sway bar, it's important this is never disturbed, set at the factory, although I have seen them broken and slipped before, so it can be somewhat reinstalled, just don't move it on purpose! I would adjust it as little as possible. Won't hurt anything though, in moderation.

Gilly

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thanks for all the great replies. the car has completely stock suspension at the moment, so it is very possible that the rear is in an equilibrium state, which is good, because i would prefer to install lowered springs at all 4 corners to ensure consistant spring rates.
i have a 4 post drive on hoist i can use, so dont worry, my innards will remaining where they belong.

cheers