The inside of the glass headlight covers were dirty on my wife’s S420, and I thought it would be good to take them off and clean them. After checking on the forum, I couldn’t find clear instructions of how to do this, although a previous posting by farena titled “W140 Headlight Lense Cover Removal???” had great suggestions by myarmar, Black97S600, and oestek to help get me started.
W140 Headlight Lense Cover Removal???
Here is how I removed and cleaned the lenses. Once cleaned, I reversed the steps to put the lenses back in place.
Step 1: Open the hood and remove the cover to get access to the lamps.
Step 2: Remove the rubber seal moulding that wraps around the top and radiator-side of the lens. The moulding has plastic clips spaced every 3-4 inches holding it in place. These come lose with a little tugging. Remove the screw holding the bottom end of the moulding. This screw also holds the lower cover (below the lens) in place.
Step 3. Remove the wiper blade. There is a plastic housing that hides the retaining nut at the base of the wiper blade. This cover is hinged to the blade and pops open with a little prying. Use a socket wrench to remove the nut and the blade will then come off. The cover below the lens can then be loosened and moved out of the way.
Step 4. Pop out the turn signal housing by reaching into the back of the headlamp assembly and pushing the release lever. The turn signal housing will push forward and dangle from the electrical wiring.
Step 5. Remove the black metal spring clips situated around the headlight cover. I had six clips (2 on top, 2 on bottom, 1 on the left and 1 on the right. Be careful not to crack the glass when removing these clips. NOTE: When reinstalling these clips, position the front of the clip then use your thumb to apply pressure to the back until it snaps into place.
Step 6. Once the spring clips are removed, gently pry the lens away from the housing. The rubber gasket should stay attached to the lens. Clean the lens and if necessary carefully clean the reflectors inside the headlight assembly being careful not to contaminate the bulbs.
Step 7. Reinstall in the reverse order.
See the attached photos for more info.