( Especially in a home setting ) blowing horn diaphragms is a sure sign that something is wrong with your system ( or the way you use it ).
The most likely cause ( of the HF failures ) is too low a crossover point . How did the diaphragm failures manifest themselves ? Were you ever shown the failed diaphragms ( if so , what did you see ) ?
Anyways, the 3115A network ( with it's 500hz crossover point ) gives too low an X-point for that small diaphragmed le85 ( especially when the driver is mated to the 2307 horn ) . ( The 3115A was just passable when a 375/2440 was used behind the 2311 / and that was just due to the 4" diaphragm size being tougher ) .
( Due to the confusion over JBL impedance naming conventions ) you need to make sure that you ended up with the higher impedance replacement diaphragms.
Do you remember what model replacement diaphragms were purchased ? What are their DCR's ?
I'd suggest you replace those crossovers with 3110A networks ( purchased used, obviously ) to raise the crossover point, @ 1/2 octave ( from 500 hz to 800 hz )
( If you are handy ), you could also build a 3110A functional equivalent using the following diagram ( courtesy of Giskard ) .
Click the pic to read the full thread ( hosting the above picture ) .