Easy preventative maintenance you should do at least every six months... unless you live in the desert..:-)
You have heard Kent harp before on keeping those water drains cleared out and flowing freely. Well here is another example of catching the problem early. Before the rust starts! If you let the rust go unattended you will have holes going into the passenger compartment.
Problem & Solution
Common among these chassis:
R107
W108 W109
W110 W111 W112 Sedan
W111 W112 Coupe
W113
W114
W115
W116
W123
W124
W126
R129
W140
W201