when i hard brake locking the weals my buggy makes a u-turn is this normal???

you probably have the rear brake set too strong. you could try strenghtening the front brake to compensate or weaken the rear brake

you can also put a peice of silicone tubing on the brake rod like this it damps the brakes a lil for smoother stops

it depends...your steering geometry could be off; on the other hand maybe some wheels lose traction before others resulting in the spin.

...as long as it doesnt do it while braking before the wheels lock then there shouldnt be a problem...once you lock the wheels the car is effectively out of any real control and will tend to spin round in the direction of any momentum it had before the brakes were hit.

basically DONT LOCK THE BRAKES

thanks guys i got it