Hard braking feels&sounds like crunching gears.

Could just be the way ABS is supposed to work,but when I press on the brakes on loose surface I can feel a grinding through the brake pedal.The brakes dont seem to work when this happens,and I cant remember if its always been like this.

Is this normal? Can I fix it?
Advice please and thanx.

Mine does the same on loose surfaces Joe, especially gravel or on the country lanes where there's a lot of loose stones on the surface.

Are you braking quite hard when it does it, or just lightly? Any TC/ABS lights come on?

I try not to use the brakes much,but when I need them and have to move in for oncoming vehicles on the back roads around my way,it can get scary when I press the pedal and all I get is a nasty crunching.I have to lift off and hope.Pressing harder doesn't seem toslow it down either.
I'm not sure if the tc light comes on,usually when it happens I'm not looking at the dash .Its not reassuring to know your brakes are the same FreeB.It would be nice to know if theres a fault I can fix.