all right i can use the cheat for repair but i cant repair the cars or any thing else with the parts like tires and engine parts dont know if it is just me or a bug
I am sure you have already tried this, but just to confirm...
When you approach a damaged vehicle, you can't use the green action commands (mouse scroll wheel) that read "Repair Wheel", or "Repair Engine", etc?
If not, then it is a bug... And it may be a DayZ bug and not just DaiyZ, too. I've read reports of vehicles states not being set/saved correctly which means you can't repair them even if you have the parts.