Electrical/starting problems

It is part of the starter assembly, it engages the bendix gear to the flywheel.
Checked the connections to the starter. The starter looks to have two connections. One with a large stud and another with a smaller stud. The connection from the larger stud to the battery is good. The connection from the smaller stud to the battery isn't good. If this is the problem, should I look at replacing the battery cable (if one is even available) or just run a new connection from the battery to the small lug?