Beverly S. Blades, chairman of the Caroline County Democratic Central Committee, was uncommitted yesterday when he made the long drive to Washington from the Eastern Shore for a "Marylanders for Mondale" reception for presidential candidate Walter Mondale.

"I'm just checking things out," Blades said cautiously.

After Mondale spoke at the Rayburn House Office Building on Capitol Hill, Blades was impressed, particularly by the former vice president's recital of all the traditional Democratic party themes.

But Blades still left the reception much the same as he went in--uncommitted--despite Maryland Rep. Barbara A. Mikulski's opening promise that "For those of you who are leaning, you won't be leaning anymore by the time you leave here tonight."

As Blades said later, "He Mondale says what you want to hear. But I'm still leaning anyway. I've got nothing to gain by jumping on the bandwagon. I've got to be practical."

Mondale so far has locked up endorsements from much of Maryland's Democratic elected hierarchy. Mikulski, Rep. Michael D. Barnes and Sen. Paul S. Sarbanes all chair the Marylanders for Mondale committee.

Also, Mondale has won endorsements from Gov. Harry Hughes, Lt. Gov. J. Joseph Curran, Attorney General Stephen H. Sachs and Comptroller Louis L. Goldstein.

Mondale's task now is to convince county-level Democrats like Beverly Blades that Maryland's May presidential primary is a sure victory, and that those still leaning had better quickly sign on with a winner.

One congressman still leaning is Steny Hoyer of Prince George's County.

Mondale yesterday reminded him in not-too-subtle terms that Hoyer needed Mondale's help during his first election campaign three years ago.

"I didn't hurt you then, Steny," Mondale chided, adding, "Even great people have lapses."

Afterward, when asked if he were still leaning, Hoyer said only, "It was a great speech."

Of the other presidential hopefuls, Sen. John Glenn (D-Ohio) is considered Mondale's strongest challenger in Maryland, though he has made few inroads, except for a surprise endorsement from Baltimore County Executive Donald B. Hutchinson.

Still, Glenn's name popped up periodically at yesterday's reception, especially among those who wanted to keep their options open.

"I think there's a big move in Anne Arundel County toward Glenn," said Gilda Atas, a member of that county's central committee. "We haven't made up our minds."

"I haven't decided," said E. Marie Johnson, a member of the Howard County Democratic Central Committee.

Johnson, a Carter/Mondale delegate at the 1980 national convention, said, "Glenn has been making some progress. I want to see what they all have to offer."

Mondale touched on most of his standard campaign themes, including a pitch for full employment, improved education and protection for the environment.

Then for his Maryland audience, he tossed in a local crowd-pleaser--concern for federal government workers, who make up a large percentage of this state's voting population.

"These fine people have been put down and ridiculed and even attacked by this administration," Mondale said. "They don't deserve that."