I've noticed that the 7443 LED bulbs are difficult to seat properly in our sockets, but I thought I had it figured out. Until a couple weeks ago a co-worker noticed that one of my bulbs was real dim until I stepped on the brakes. When I got home I checked and the bulb almost fell out of the socket. Strange. So I pulled out the original incandescent bulbs and as I was putting them back in I noticed that the incandescent bulbs had a 'ramp' that led up to the main bulb area. So I took the LED bulbs inside and compared a bunch of measurements including holding them up to a normal incandescent bulb.
I ended up digging out the dremel and modifying the LED bulbs and now they fit much better. The 'snap' into place like an OEM incandescent.
Pics below showing the LED bulb with the normal "shoulder" area and then the one with the wires bent away (to make it easier to grind with the dremel) and the slope I ground.
Hope this helps others that have gone to LED bulbs.