Brake problem

With all this rain I thought I'd go do some fords, so I went to go in my 2.5td 90 and went through a puddle first (Not much higher then a kerb stone) after I put me foot on the break quite heard to be met with a massive metal grinding noise. Continued to drive no more then 30 yards and tried my brakes again, no grinding this time but the front passenger wheel locked up pulling me to the passenger side.
I'm hoping it's just a worn brake pad, but can anyone offer possible problems?

Thanks.

strip it down and find out mate , no chances with brakes .

Turns out it was a seized piston and worn pads plus a spring had gone in the rear. Oh well they work now which is the main thing.

Just found and was going to guess caliper - glad you got it sorted