left front wheel getshot and smokes after about 30 miles,

minkyb00tle

I have changed brakes , calipers , wheel bearing , axle ,

Mr_Shiftright

I would suggest jacking it up when it's hot (be CAREFUL not to touch the rotor!) and try to spin the wheel...if it's dragging badly, then open the brake fluid nipple. If the wheel runs free, you have a hydraulic pressure issue (perhaps from the master cylinder, or a compressed brake line). If the wheel still drags, then a caliper slide is sticking (did you grease the slides?) or a caliper piston is sticking.

You can check wheel bearings by grabbing the tire at 9 and 3 o'clock and trying to wiggle it. There should be very little play, if any. You might also double-check that you did not tighten the wheel bearing nut too tightly.