Welcome to the Q&A Forum

If you can, then modify those links and direct them to the main domain. If not, don't put much effort...rather, I would advice you to invest that time in creating new more relevant links which can help you more Also,  there is no difference between a 301 and a link in terms of PageRank dilution. According to Matt, if you have many redirects, like chains of them from one url to another to another, that is a known bad thing. But one or so won't hurt you. Here is video link where Matt has answered the question- What percentage of PageRank is lost through a 301 redirect?- https://www.youtube.com/watch?v=Filv4pP-1nw