Problem GMC Safari 97 brake and steering wheel

That such friends I have a GMC Safari 97 when brake and try to turn the steering wheel and loose the brake and try to turn grooves and vibrates and the brake does not grab
1.-Check the level of power steering

oil


. Power Steering will be damaged the hydrobooster
and the master cylinder

check the brakes and are well as tiles and cylinders ............... thank you very much greetings