The only experience I have contact here in the tropics has been with an 300 E 4matic the previous owner of the local M.B. dealer brought for himself.

From the day one the car started giving all kinds of problems with the 4matic system. After one year the car was returned to Germany. I remember that the techs at the dealer talked about this test valve and heard the comment that it should only be used for tests and maintenance. The owner wanted to disconnect the system, but it was not as simple.

The other option recommended by Michael Cole seems more adequate, although I remember also comments about the planetary gears suffering from premature failure if the 4matic system on W124s was used disconnected or with a reported failure by the computer.

Now, having owned several M.B. wagons I can tell you it is not advisable nor safe to drive with the rear self levelling hydraulic system disconnected.

Yes, the rear self levelling suspension does regulate the height of your rear axle upon the current load on the vehicle. Although, it doesn't mean the system only works when the car is loaded. The system works permanently and is what provides cushioning and control for regular driving. If you turn off the system, you could still drive the wagon, but it will become extremely hard at the rear providing a very umconfortable ride. Also, it will generate premature ageing on all suspension components.

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A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]