Originally Posted by AyeCaramba

Timings for your connection are fine - AA will protect you anyway. Immigration can be a mixed bag at LAX (I've had anything between 10 mins and 2 hours) but your schedule should be fine.

Even if your bag is checked through from LHR you'll still need to claim it at LAX to take through customs - in theory you can drop this off at connections but I'd pick it up then take to AA to recheck for your onward flight

You'll arrive at TBIT (ETA - I'd thought you were incoming on BA so arrivals at TBIT is correct. If you're on the AA arrival this could land at either but (I think) you'll be routed through TBIT to clear immigration and customs) and (most likely) depart from T4 - these buildings are next to each other and it's a 5 min walk. Once you come out of customs exit TBIT and turn right directly out of the building. The next building you'll come to is T4 - take the escalator up one level to departures and you're there


Don't forget to pop into the Flagship Lounge if you have time - it's one of AA's best lounges in North America