Went off roading. Came home then next day went to drive and when brake pedal pressed half way to the floor the brakes lock up. I dnt know what can be causing it. When I went through a puddal it was fine then after the brakes dry it does it again. and its never done it before. when i press on my brakes i hear a gringing noise too.

 

Water in the brake lines can cause this, mud or dirt on the pads can also cause this as well as the slides on the calipers being devoid of grease. If it were me I would pull the wheels off and inspect the condition of the brakes, and if they are ok I would lube the slides and put it back together and see where that gets me.