Are you talking about the bulb not staying in the light housing? If so, the new bulb is packaged with a rubber seal. I originally though the seal was just packaging for the bulb. I tried to put the bulb in the housing and quickly figured out something was missing. Put the rubber seal back on and it fit perfectly.
If this is not what you meant, try and describe a little better as to what you mean. I just installed two of these kits and they are fresh in my head. So, I can probably help you troubleshoot the problem.