Reference sludge trap screws, based on my A7SS small journal crank there is no tube inside as such, just the screws either end that form a seal. If there are no slots you might have to drill a hole in them and extract them out.. then just flush out the internals and fit new end plugs. I center-punched the edges of the new endplugs on mine a few times to make sure they wouldn't fall out, as I wasn't to confident about relying on threadlock for that..