my tractor wont steer all the way to the right??

On a Sears that means the cheap steering system Sears use has worn out. You need to replace parts if you can get them. You can see a picture of what it looks like on the Sears Parts site. It is basically a small gear on the steering shaft and an odd shaped gear it turns. I would replace both of those and all the bushings that those parts ride in/on. Roger

Is there any way you could get to a point next to or under the tractor, with it not running and safely blocked so it won't roll of course, to where you could see the various parts of the steering system, and have someone else turn the steering wheel from side to side while you watch what's going on as the parts work together? This might give you a better idea of what is, or isn't working as it should and could help you determine what you need to fix or replace.

i looked under it but still cant see anything , im pretty sure something is bent or wore out for it not to turn all the way

It's interesting that it steers the full amount when the weight is off the tires. Could there be anything binding up as more weight is applied? Maybe the spindle bearings on the front axle are bad and it is binding up with weight on them?

If you have a way to do it you might take the weight off of one front wheel at a time and see if that makes a difference in how far it will turn.

O.K., so we have a pretty good picture of what it looks like, how about how things sound when you're turning the wheels? Are there any groaning, screeching, grinding sounds like things are too tight, too loose, cogs not meshing, just plain in need of some lube?

ok finally got some time off to check the tractor out.. heres what i noticed with the hood up and looking down and the steering assembly rod.. when i go to turn left there is no movement until i actually move the steering wheel. but when i try to turn right you can see alot of play from the steering pin and the draglink.. im guessing the play it has is the steering im missing..

Could be a gear tooth missing or worn badly on the half moon gear plate that intersects with the gear on the steering wheel shaft. Like Roger mentioned I would probably replace both of those at a minimum. Thing is you probably have wear in all the pivot joints from those gears clean out to the tie rod ends on the wheels.

Little slop in this joint plus a little more slop in that joint and even more slop in another joint all adds up to a lot of slop. In the end it will probably be easier while you have it apart just to replace all the joints and connections that look worn rather then try to solve it one piece at a time.