cdsjklee

Hi, Anyone have any idea why front lowers by itself after sitting for few days. It never happen before but now it lowers by itself.

am_beagle

Air suspension failed ?
If so, check the compressor.

vettdvr

I think you have a defective front shock/air suspension.

The compressors are very reliable. The rubber on the air bags is not. I just replaced both of my rear air springs for the same problem.

If you aren't getting a warning in the FSS you will soon.

~CL500~

Your SL55 has Active Body Control, so it's a Hydraulic suspension, not air. What you describe is pretty common and is due to either your front or rear ABC valve blocks. The valves should remain closed when you turn the vehicle off. If the fluid is dirty or of the valves are faulty, then fluid slowly returns back to the reservoir after you turn the car off, thus lowering the car. When these symptoms occur inside a 7 day window, then MB recommends that you filter the ABC fluid first. If that does not resolve it, then replace the faulty valve block.

To filter the fluid, replace the ABC filter with the 3 micron type. Then run the rodeo program in SDS for 2 consecutive runs. Finally, replace the ABC filter again. This ensures that all of the ABC fluid has traversed the filter and was cleaned.

Good luck!

cdsjklee

Problem solved. Car did not start this morning and call the Roadside assistance found start battery was bad. Replace the battery. It was battery problem they said.
Fixed with under $ 200.00. Not bad for the Sl55.

Thanks