Occasionally when l brake suddenly, my '09 BT50 4x4 will shudder through the brake pedal. Is this just the ABS or a potential problem? Anyone know about this sort of thing........
Sounds like the ABS to me, from your description.
Thats how they're designed to work so you still have your steering under emergency braking.
If you're really concerned, have them checked.
To be cynical though, they'll normally find a prob.