I have the same problem with my jackpost holes on my 300E. Bloody road salt.

I have not yet tackled them, but thanks to all for the info here. I'll likely do something similar. When I first noticed them rusting a couple of years ago, I had the underbody chassis undercoated and asked the guys to spray a bit of undercoating (essentially oil) into each jack hole. It worked wonders for slowing the corrosion down.

I'd maybe echo the recommendation to spray a bit of tacky oil into the inside of each tube and then replace the caps. I wouldn't drive it around without the caps in. All IMHO.

__________________
Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon