Last weekend I decided to take apart my Bosch
ellipsoid headlights (that came stock with my Euro car) as the lenses had
gotten dusty throughout the years. Here is a short write-up on the it. I
thought some of you might find it useful.
Firstly, you have to remove your corner lamps. Remove the
indicator lamp bulb, then use a screwdriver to pry the clip that holds the
indicator lamp free. Slide the indicator lamp out forwards.
You can now remove the headlights. To do so, you need to remove
the 3 screws that are on the top, and two on the side. On my car, they
were all Phillips screws. The screw below the indicator lamp area is quite
hard to get to. It would probably be relatively easy if you have a short
Pull the headlamp out towards you, then disconnect the connectors. Set
your precious headlamp down on a soft, gentle surface!
There will be 2 small metal clips on both the top and bottom of
the ellipsoids. Unclip them by prying them off with a flathead
screwdriver. Remember to pry from the plastic end because you might
break/chip the glass if you apply too much force on it.
Unhook the 5 big plastic clips (3 on top and 2 on the bottom)
with a flathead screwdriver.
You should now be able to separate the lens part from the
reflector part of the headlight. Pull them in separate directions. They
might be tight, so wiggle them free.
This is how your headlight will look like when it has been
Notice that both lenses are held in by factory silicone. Using a
blade, slice them off. Your lenses should now fall out quite easily. If
they don't, you can use a flathead screwdriver to gently nudge it out. Be
very, very careful!
Clean the insides of the headlight thoroughly. I sprayed window
cleaner then used newspaper to wipe it clean. You may want to wipe the
projector for the low beam as well. Remember to wipe underneath the
projector lens! You will see a definite improvement in clarity.
Make sure you have gotten rid of most, if not all, of the
factory silicone. Put the lenses back into their original positions.
Double check by looking at the orientation of the other headlight. Now,
apply new silicone (I used Selley's Marine Sealant silicone) to the rim of
the lenses (where the factory silicone was before). Let the silicone dry,
then make sure the lenses are secure.
Double check for any smudges on the glass, then reassemble in the
reverse order of disassembly.
Now, let's make a comparison:
Dirty Left Ellipsoid
Clean Right Ellipsoid