As they did for five years earlier this decade, Republicans M. Tom Shimizu and Mike Stewart again will work together as members of the Salt Lake County commission.

Shimizu, as expected, handily defeated Democrat Dale F. Gardiner and Libertarian Gary Root to win the two-year County Commission seat he gave up in 1986 to run unsuccessfully for Congress.Stewart turned back a surprisingly strong bid by Democratic challenger Jim Bradley to win his third four-year term.

When sworn in next January, Shimizu and Stewart - with commissioner Bart Barker, whose four-year term ends in 1991 - will reconstitute the County Commission as it stood from 1981 to 1986 and will end the Democrats' single-term control of the two-year seat.

With all precincts counted, Shimizu, who held a commanding lead in the polls throughout the campaign, finished with about 155,935 votes, or 58.5 percent, according to complete but unofficial returns.

Gardiner, the mayor of Riverton who was drafted by the Democratic Party to replace former Commissioner Dave Watson as a candidate, got 39 percent. Watson gave up his re-election bid after a May arrest on drunken-driving and drug-possession charges.

Root was the choice of 2.5 percent of the voters.

Gardiner, an attorney, said he was proud to represent his party although he had not intended to run.

Salt Lake County voters had a choice but chose the comfortable, business-as-usual Republican leadership, he said. This race was likely his last political contest.

"This was the last hurrah," the Democrat said. "I'm up for re-election next year but I don't think I'll run. Eight years is enough. The town needs some news ideas."

An elated Shimizu thanked county residents for their vote of confidence and pledged to work hard with his once and future commission mates.

"It's a very favorable situation," he said of working again with Barker andStewart. "When you get three different people with different backgrounds working together, it's like a family. Even within the same party we'll have disagreements, but we'll work them out; not go grandstanding in the media."

Stewart had a much tougher time fending off the determined Bradley, a former director of the state Energy Office under Gov. Scott Matheson. The Republican incumbent trailed in early returns from heavily Democratic districts in Salt Lake City and the west side of Salt Lake Valley before finishing fast in traditionally Republican districts in the south part of the valley.

Stewart got 137,808 votes, or 52 percent, while Bradley, who in recent weeks had pulled much closer to Stewart in opinion polls, tallied 48 percent, trailing by some 9,000 votes. The commissioner credited Bradley with running an intelligent and energetic race.

"He did some direct mailing and targeted groups that may have been upset with some (commission) decisions over the past couple of years," Stewart said of Bradley. "Nothing is sure any more in county politics any longer. The county is too volatile, too fluid."

Bradley wasn't surprised by his strong showing and said he won't rule out future political races.

"I'm glad we gave the troops something to cheer about for awhile," he said of his early lead. "I knew it would be close because I was pulling stronger than the polls showed. I did everything I could and have no regrets. I enjoyed the campaign and appreciate the fact that Mike Stewart and I ran one of the most positive campaigns around."

County Clerk Dixon Hindley estimated as many as 75 percent of the 355,000 registered voters in Salt Lake County cast ballots Tuesday. The heavier-than-expected voter turnout kept some polling stations working half an hour past the 8 p.m.poll closing.