I have configured policykit before.
I have /etc/polkit-1/localauthority/50-local.d/50-localauthority.conf
with the contents:
[filesystems mount internal privs]
Identity=unix-group:mygroup
Action="">
ResultAny=no
ResultInactive=no
ResultActive=yes
It enabled me to mount my internal drives in nautilus without typing
the admin password. But it doesn't work now.
Perhaps try this?
make sure udisks package is installed.
vi /usr/share/polkit-1/actions/org.freedesktop.udisks.policy
Edit the section
<action id="org.freedesktop.udisks.filesystem-mount-system-internal">
change...
<allow_active>auth_admin_keep</allow_active>
to...
<allow_active>yes</allow_active>
I have been holding policykit but as you mention you cannot due to dependencies then I am not sure what to suggest sorry.