Hey guys picked up an 05 e500 today and noticed the rear air drops after setting a day. The front is fine. It pumps right back up quickly after starting it. I bought the car from a salvage auction and the front bumper cover is torn off so first thought it may have a damaged air line on the valve that is by the compressor. Looks to be untouched. I sprayed soap and water all over the lines on the valve but found nothing. Only thing I can think is the rear bags are just leaking. Is it pretty common for those to fail with age? the car has 140k but looks to be well taken care of. This is my first mercedes so I'm new to this car. Just wondering what the common fail points are on this car as far as suspension. Thanks in advance.