The good times are easy for any family. It's the bad times that pose a test. So, it is a pleasure to observe that the worse the Pittsburgh Pirates play, the more they act like a genuine family.

For almost a month, the Pirates have been as bad as they can be -- 7-18. No, make that worse then they ever believed they could be, at least in a pennant race when it really mattered. Instead of unraveling, they have darned and mended their fraying ball club time and again.

Again this afternoon, just when they could have taken a final pennant-race gulp and gone down for the last time, they battled commendably and showed the Montreal Expos that a champion may go down, but he goes down hard.

It should have been the Bucs who were worried, tenative and self-destructive today, and the Expos who were ready for a kill. Instead, Montreal showed all the worst traits of past pennant races and lost, 4-0, to the Pirates' big right-hander, Don Robinson.

A dual temper-tantrum ejection of Manager Dick Williams and Rodney Scott was the Expos' only offense all day. "We're down, but we're not out," said Phil (Scrapiron) Garner. "We had to win today. And we have to win tomorrow. Otherwise, our backs are really against the wall."

To their credit, that is when the Pirates play best. They still trail the Expos by plenty -- 3 1/2 games and four in the lost column with 19 to play. And they face a pitcher -- Tim Gullickson -- on Sunday, who fanned 18 men in his last game.

But the Pirates know one of the interior tricks of the game. "We know how to win . . . and we know we can win," said Garner. "That's way it's so important not to let the Expos know that they can win, too. They have everything but that last bit of confidence -- especially against us. We can't let them get it."

Minutes before this game, Dave Parker and Phil Garner were staging one of their mutual defamation attacks, Garner telling Parker, "Your hitting has gotten as bad as your fielding always was," and Parker dismissing Garner as a "Punch 'n Judy midget."

"That's when I knew we'd be all right," said Pirate Manager Chuck Tanner. "I told Parker, 'You and Gar were at your best today.'"

Parker shouldn't have played today. He should have called in sick the way Ellis Valentine and Ron LeFlore have this weekend -- nursing injuries that are hard to find and harder to describe. Bruises and such. Parker sat on his stool after the victory with ice bags on his left knee and right ankle. In the ninth, he had to wear a batting helmet to the outfield after "apples, cans and ice" were thrown at him.

"You put yourself on the line everyday," Parker said. "If you're going to go down, then go down proud. Even if we don't win this thing, we want to be there right on the Expos' heels down to the last day."

Actually, the Pirates looked today like they were in first place, while the Expos, who may have the surliest nd most internally divided clubhouse of any contender, acted as though they were the last-gasp desperate team.

Scott was ejected for -- in the umpire's words -- "saying little things constantly." That's easy to believe. After Scott got chased for his mutterings, Williams had to come to his defense, throwing a Weaver-like tirade. "It looks like this umpiring crew is laying for Rodney," said Williams. "I have to protect him."

What Williams really wishes is that he had a clothespin for Scott's smart mouth. Who needs a whole angry crew of blueclads on a team's back in September? The Pirates would never be so tactically foolish. Yet, after this game, Scott was still vilifying each and every ump by name.

"Rodney asked (ump) Terry Tata why he had a chip on his shoulder," said Williams. "So Tata cursed him. I told him, "That's bullfeathers,' When I came out, he told me I was bullfeathers, so I told him he was the same thing right back.

"So, said Williams, "he ejected me for saying the same thing to him that he already said to me."

How could that be explained?

"I guess," said Williams, "it dependson what kinda bullfeathers you got."

When it comes to a pinch, the Pirates don't talk; they play. Mike (Hit Man) Easler homered in the second inning. John (The Hammer) Milner singled home Easler in the seventh. And the Bucs added two insurance runs in the ninth as Parker doubled. Easier singled him to third, Milner plated him with a hit, and Easier then scored as the easily-ruffled Scott was botching an easy inning-ending double play pivot.

"Being 3 1/2 games back is nothing," said Easier, who upset an Expo pitching staff that had a team ERA of 1.96 for September (and a 9-2 record) entering this game. "We'll pass 'em if it takes to the very last day of the season."

This game had a perfect Pirate feel because the mammoth Robinson, at 6-feet-5, 240 pounds, was hurling. The proper Buc pitchers are of the intimidating sort, like 250-pound Jim Bibby and 6-7 John Candelaria.

"I like pitching in this park and I must like pitching in September," said Robinson, who beat the Expos here, 2-1, in a vital meeting last September. It is also typical of the Pirates that they seem to rise to the occasion no matter how dismal they had been all year. Robinson is now 6-8 and had just one complete game in his 19 starts before today.

How do you explain that?

"I can't," said Tanner. "We seem to play best when the most things are against us. Face it, the Pirates are just tough people. That's why they're world champions until somebody takes it away from them. And nobody has."

A year ago, the Pirates exuded confidence, if such a thing is possible. In recent days, they have seemed to exude lost confidence. Those self-doubts have not disappeared. It merely seems that the Bucs have decided, as Parker says, to "go down with pride."

Against a team with as little pride as the Expos, that may be a major advantage. Even the Expos' Woody Fryman says, "I don't know what it is for sure, but I get the feeling that a lot of the guys aren't sure we'll win yet. They're looser than they were last year, but, you know, there's still a few of them just showing up in time for the game and things like that.

"If we can win two of the three here, then maybe they'll change their attitude. If our guys start believing and get with it, then we can go all the way."

You could fit the Expos' heart in a resin bag. The Pirates have been snickering ever since they got here about the absences under stress of Valentine and LeFlore. Tanner broke up the Buc bench with the announcement that LeFlore had decided to put his bruised wrist in a temporary cast to heal during exactly the three days that the Pirates were in town.

"Gee," said Tanner, "after all the things he said (in Inside Sports) about how dirty (Tim) Foli is and how he wants to break his leg, you'd think he didn't want to slide into second when Timmy has the ball in his hand."

"Whatever happens the rest of the way, we'll go through it together," said Garner today. "All that "family and togetherness was easy last year, 'cause we were healthy and we were winning.

"The proof came this year with the Blyleven incident," said Garner. "We always said that we'd bust our tails for anybody in a Pirate uniform, regardless of what we thought of them personally. Well, after Bert quit us, and then came back, we proved it.We've stuck behind him. When we've had injuries, we haven't passed the blame to other guys. We've shared the blame like we shared the credit.

"When you're losing, you can have disagreement or you can have dissension," said Garner, the team's player rep. "There's no third choice. You can have your arguments in public as disagreements, like we do, or you can talk behind people's backs. That's dissension. We've done our chewing-out to each other's faces."

The Pirates have many problems, to be sure. Robinson's four-hitter today gave the Bucs' whole staff a paltry 22 complete games for the season -- the same total as Oakland's Rick Langford.

They can't match the hurling of the Expos, who already have pitched five shutouts in September. And they don't have Willie Stargell. But at least, all the Pirate problems are real ones. None are "internal."

"Sure, we're frustrated. We're pressing. One day somebody says, 'Just relax' and the next day they say, 'You're not being aggressive enough,"' said Garner. "When you lose that good peaceful feeling of being relaxed and aggressive, it's hard to get it back. There's no question we've played lousy recently. But we won't give up. We'll stick together all the way."