The repository does not support directory listing, hence the 404. If
you want to manually browse the repository, you must specify a file
name, like:
http://dl.google.com/linux/rpm/stable/i386/pubkey
Does that work for you? Yum and other package managers know what files
to request, so should not have issues with the lack of directory
listings. If you get any errors using yum, please let us know.
- Google Linux Repositories Guide