Bolt size for the Weerider Kangaroo I lost the main bolt for a Weerider Kangaroo, just wondering if someone has one and can tell me the size of the main bolt the one that attaches the seat to the bar.
I would urge you to check online, and order a replacement from WeeRide. Parts like this are hardened more than standard hardware grade steel.

If this was a reflector screw, then I'd say grab anything from the local hardware store. However, in this case there's a lot more at stake and you don't wanna cut corners.

I have no experience with WeeRide, but I have gotten replacement parts from other companies sent to me, free of charge, when I inquired online.

http://www.weeride.com/Kangaroo-Center-Mounted-Child-Bicycle-Carrier