If the senate majority leader is refusing to do his job, can the other Senators vote to expel him or force a vote for new leadership?
Yes. The following are all options I'm aware of:
A 2/3 of the Senate (67+ votes) can vote to expel any sitting Senator as per Article 1, Section 5 of US Constitution. An expelled Senator can of course no longer serve as a Majority leader.
"Each House [of Congress] may determine the Rules of its proceedings, punish its members for disorderly behavior, and, with the concurrence of two-thirds, expel a member."
This requires at least 17+ votes from Majority party in 50/50 Senate, and at least 20+ Majority party votes in current 53 majority Senate, assuming that 100% of minority party unanimously agrees.
This is the only option available to influence directly to members of the minority party, obviously with participation of at least a meaningful part of majority party.
All other options are 100% outside the control of minority party senators.
A Majority Leader can be pressured to resign from the position voluntarily (Trent Lott was, for example).
A Majority party caucus votes to elect a new Majority leader every 2 years, during Congress change. Majority party can then choose to elect someone else.
In theory, Majority party caucus can vote to elect a new Majority leader (as they are the ones who decide who leads them) at any time. I haven't found a single case of that happening, but also no mention of any rules preventing that.
A combination of other effects (party switching, impeachments, resignations, deaths, next elections, etc...) can cause opposite party to take Majority.