The best still fails

[Cummins12V98]

" Later I added a bed saver to the rear."

ZERO reason for one with that hitch or a B&W. You have to be blind to not see if it's properly hitched with either one!

 

[jacknife]

DOUBLE JAWS SINGLE JAW a moot point one is as safe as the other. Maintenance is the key . I have seen so many rusty fifth wheels and king pins I have lost count. Rusty king pins and rusty jaws contribute to loss of contr0l and jack knifing. Grease the king pin and the jaws . Not Wd 40 or something along those lines . Use real Grease ! It works !

 

[HPSimpson]

I use marine grease on the jaws keep them well lubed.

 

[TFucili]

Lubriplate Extra Heavy Gear Shield makes great 5th wheel grease.

 

[SmithSpecialtiesHotShot]

Two factors.
Physics. and age/maintenance of the hitch.
First that hitch looks worn out and maybe had been corroded by road salt that sat too long, or never got washed off from the hidden parts of the hitch.
But I think the explanation give the biggest clue (Towing car trailer that went off road/ditch?). It wasn't about towing weight. It became about sheering forces of a a trailer that probably over-rotated in the jaws and something had to give.
Kind of like what happens when you use a 5 ft crowbar to pry two boards apart. The further away from the fulcrum you are, the more the forces were magnified.
This is why the military uses a pintle hitch on practically all off-road trailers. A pintle works by joining two rings (one on an X axis, and one on a Y axis) which can each rotate 180 degrees independent of each other.
Inspecting the hitch and keeping it clean of salt and corrossives would have helped, but frankly it just looks worn out.