How do you get the wheels back on?

Ok a total noob question I know but I don't want to break anything. I purchased a collection off someone several years ago and one of the cars was missing two sets of wheels. I have since gotten replacement Marklin metal wheels but I can't seem to work them back into the truck. The center 'forks' seem to always want to bend down preventing the axle from slipping in between them. Any tricks of the trade someone can share?

What you want to do is position the wheel set right on top of the slot in the 'fork' and push straight down. This should open the slot and the axel will fall in place. But if the fork bends in preventing the wheels set from dropping into place, then use a small screw driver or pointed tool to help keep the fork open. Sometimes, I have had to use the tool to open the slot slightly before dropping the axle in place.

Rob

All the ones I have changed is like Rob has said, they press in. I have had a few that wouldn't go in, so I placed one side in and had to push out a little on the other side of the truck and press down and they would go in place. the clips are really tuff I thought it might break but so far none has.

Thanks Guys!! With a little prying of the 'forks' and a little more pushing and persistence, I got the wheels back in. I was indeed surprised how much force it took to push them in and that the trucks and wagon are far more durable then the small size would make you think.