There are rubber O rings in the disconnects and if they get damaged by debris while connecting, they will need to be replaced. I happen to have two on my desk and one is a Kubota supplied one and the other is by another supplier. One has two rubber O rings and the Kubota one has what appear to be a white plastic ring at the close end and a rubber O ring at the bottom end. If the tractor is still in warranty, ask them to replace the fittings, rather than repair them. I don't know if repair parts are even available. Replacements are about $25 for the two halves.
If the leaks are from the threaded parts, have them removed and use a good quality pipe sealant on the threads or teflon tape.