Take you meters to meter repair shop and ask them to service it. Actually the problem is with the back plates, they usually get blurred due to age. So no matter what did you install, the back plates will reduce the light by 30%. LED has brighter light, but it is uni-directional, that is you will find more light at the focus point than the surrounding area, light will not evenly disperse.
If you want to install LED, get LEDs (any color) = number of bulbs + 470 Ohm resistance for each LED, put the resistance in series with any terminal of the LEDs and fix them in the bulb holders instead of bulbs. Since LED are polar, if the LED does not lit up, remove the holder and re-insert by rotating at 180 degree. This is to achieve the correct polarity.