I am 50% owner of a family vacation home valued at about $500K. I would like to sell my share to my other family members, but they are about 20 years younger than myself and in no financial position to buy me out. I am looking to relocate south and would like to know if it is possible to take out an equity loan against my share of the vacation house? It has no mortgage and has never had a mortgage. Any advice please?

A lien can't be placed on a part of the house. All the other owners would have to consent to the lien. That doesn't mean they would be obligated on the debt, but if you didn't pay for any reason, they could lose their share of the property.