docgboy

you need to move the collars up on the main strutts to move the gear slight more forward. This will lock the gear in the down position. Air pressure alone will not keep the gear down. You may need to adj the rear of the gear mounts tp get the gear to retrct fully into the bays. Don't try again with the gear set in the same position or it will continue to happen.
Also the plane needs to set on the mains in a level attitude on landing and no up elevator and sometimes I add a little down when she touches. If you try a 3 point landing or land pull on the up elevator it will bounce every time.
Just telling you from my experiences.
Scott