Stablize a 3 pt hitch

[slider909]

The main problemis where the arms are attached to the tractor, there is quite a bit of play in that fitting. This is where I put the washers, 4 helped somewhat. But there is still quite a bit of sideways play.

 

[GPintheMitten]

If the lift arms are moving side to side too much, then you can shorten the stabilizer arms.

I pull both middle pins, attach the implement, raise the implement slightly off the ground. Then I push the implement to the center and put in one pin. Then I move to the other side and push the implement the other way toward the middle then pin that side.

 

[Baby Grand]

If the lift arms are moving side to side too much, then you can shorten the stabilizer arms.

I pull both middle pins, attach the implement, raise the implement slightly off the ground. Then I push the implement to the center and put in one pin. Then I move to the other side and push the implement the other way toward the middle then pin that side.

^Exactly what GPindaM said.
Also, make sure the shanks of those bolts are a "running fit" with the holes in the stabilizers.
If not, swap them out for bolts with larger diameter shanks.
You want a close fit to reduce slop and wallowing the holes.