WASHINGTON (CNN) -- Leaders of the AFL-CIO urged their individual unions Wednesday to hold off endorsing a presidential candidate until the AFL-CIO General Board votes to make a formal endorsement in the fall.

The move is part of a broader plan to increase the influence of grass-roots members in the endorsement process while keeping the labor union united behind one candidate -- avoiding the division that marked the varied labor unions' endorsements in the 2004 nominating process.

"We are asking each of our unions to reach deep into their membership and provide opportunities for working people to evaluate all the candidates -- and for candidates to hear directly from them about working families' concerns," AFL-CIO President John Sweeny told reporters at a press briefing.

The AFL-CIO Executive Council, meeting in Las Vegas this week, will formally vote later Wednesday on the policy that asks its 54 individual unions not to make an endorsement until the conclusion of a sixth month process involving several candidate "discussions," culminating in a major Chicago conference in August.

"We're not going to act as individual unions," AFSCME President and AFL-CIO Political Committee Chair Gerald McEntee said in the news conference. "What we're going to do is involve our members in the decision-making at every step of the endorsement process."

In the 2004 Democratic presidential primary, union support was mostly divided between former Vermont Gov. Howard Dean and for then-Missouri Rep. Dick Gephardt. Sen. John Kerry, D-Massachusetts, went on to win the Democratic nomination.