How do you disconnect the ABS when off road?

When I was offroading in 4WD low ratio climbing a steep greasy gradient, lost traction, put foot on brake pedal, the brake pedal was solid like a brick had been placed underneath it. We had no brakes coming back down. Tried to pump brakes but were still solid. Has this occurred to anyone else ? Could this be an ABS fault ? We don't want to remove any fuses as this is unsafe. This happened 3x going uphill during the day. Please help with advice if you can. Popey
 
My 2012 Rubicon disconnects stuff at the touch of a button. Ha ha.
I cannot see a logical reason to disable the ABS, that prevents locking-up the brakes, that has saved my ass a few times, on and off road.
Oh, Traction Control, goes off in 4X4 which I always use off road.