Bowed Garage Door Frame Leaving Gap Between Wall and Frame

[yartin]

My garage door frame is bowed at the top so there is a gap of around 10mm between the brick wall and wooden frame. it's old garage door of around 2m height and the bowing starts from around half way of the frame and goes to the top. The old screws and plugs have come out and looks they are the wrong screws as they are short and even worse as a couple of them are screwed to the mortar between bricks.
The door frame is 3" X 3"
Is it possible to straighten the wooden frame using coach screw with socket head and metal washers?? Basically force the bowed part of the wooden frame back to straight position. If so what coach screws size should I use? I was thinking of M8 * 110mm

Thanks

[yartin]

After doing some research, seems there is a better way to straighten the bowed frame in case the coach screws will break or split the wood. Use another post of 3"x2", attach it to the garage frame and then insert 3 coach screws plus washers into the post and frame to wall and slowly force the coach screws in to straighten the bowed frame. Will this work?
Any expert advice appreciated.