First Gear uses press on axles and wheel sets. They have a knurled or splined axle that holds the wheels onto the axle. If you have a bench vise or a raised concrete walkway you can set the axle on, you will only need to take the broken stub of the wheel set off the axle and slide the axle through the chassis. If you have the bench vise, Just set the bent axle into the vise horizontally and close the vice jaws to straighten the axle. If you don't have a vise, you can use the concrete method. Lay the axle on the concrete with the tires up against the edge of the walkway or concrete slab. I use a 22 ounce ball peen hammer when straightening out the large scale axles, but much prefer the vise.The wheel set is going to be a bit of a challenge. If you have all of the plastic parts, you should be able to use them to reconstruct the wheel set. I any parts are missing, it's gonna be a bit of a pain to fix it. Is this a five hole disc wheel or a spoke wheel?