hard rocking noise in braking & pedal wobbling

[08 Hilux Surf]

I basically take the same daily commute to my work with my 08 SE 4Runner. Every once in awhile I drove over this small pot hole when coming to a stop sign, and as I press my brakes while driving over the pot hole I hear a loud rocking(clank?) noise and actually can feel my brake pedal wobbling... This does not always happen, but the brake pedal wobbling bothers me. Anyone know about this noise and brake pedal wobbling?

 

[Acidmeld]

Thats your ABS kicking in. When you go over the pothole holding the brake the wheel locks up. The ABS is pulsing the brake to unlock it. Just doing its job...

 

[08 Hilux Surf]

That was my first thought, but just thought it was strange since it doesn't always happen. One of those pot hole I try to avoid, but sometimes I just can't due to the traffic. Thanks for the re-assurance!