12&16a New York racetrack's burst tank problem?( 7,4) ??L???T, ?A?K
19a Spy author with weight at top Aussie reactrack(10) ?L?????T??
28a French racetrack stretched winner (9) L?????A??
29a Patron following up at Northern Irish (11) ???N?????C?
Apologies for lack of letters, bit of a stinker today!