[rheavn]

I have not discovered a single air line burst or split either.  I did find a rubber brake line chafed through.  99% of the air leaks I have found were without getting under the coach.  Replacing push in fittings is a no brainer---they leak.  Only replace with good quality DOT compression fittings.  Don't forget to check inside the coach.  Parking brake valves can leak.  Brake pedal valves can leak & mine had leaky push in fittings.  Air doors, toilets, etc.

The only push in fittings I have on my coach are on the dump air valves.  Never found a compression fitting to replace them.