Bill McCartney, the head football coach at Colorado, is just the sort of no-nonsense, tough, hard-working disciplinarian one would expect from a former Bo Schembechler protege.

He's not content with the dreaded fall two-a-day practices; he has three-a-days. He's suspended so many players that it's difficult to keep track of all the coming and going. McCartney's style on the field is equally tough: pound 'em with the run, stop 'em with hard-nosed defense.Four years ago, ignoring his critics, McCartney abandoned a state-of-the-art pass offense for the wishbone - the football equivalent of trading a BMW for a Bronco. Success has since silenced the critics. After some more tinkering with the offense, McCartney has rescued the Buffaloes from the dark days of Chuck Fairbanks and returned them to the national rankings and to the bowl scene. On Thursday night, the the Buffs will meet the BYU Cougars in the Freedom Bowl in Anaheim Stadium.

This was supposed to be a rebuilding year - only three seniors start (another rotates in at wide receiver) on this year's squad. But after surviving another wave of suspensions, a two-week jail sentence for their quarterback, yet another change in

their offense and heavy graduation losses, the Buffaloes produced an 8-3 record. "A couple of bounces here and there and we could have been a 10-1 team," says quarterback Sal Aunese.

The Buffs' only losses were to the Big Three of the Big Eight Conference, and two of them were heartbreakingly close. They lost to No. 4-ranked Nebraska 7-0 after committing two huge fumbles. They lost to No. 10 Oklahoma 17-14. But they were routed by No. 12 Oklahoma State 41-21.

In the meantime, the Buffs managed to claim three come-from-behind victories, against Iowa, Oregon State and Colorado State, while beating up on the rest of the hopelessly weak Big Eight (CU finished fourth in the league standings).

It was the team's best season in 12 years - and next year should be even better. "It certainly promises to be a year that we've been waiting for," says McCartney.

Colorado operated a solid football program in the '60s and mid-70s, but in 1978 the school sacked Coach Bill Mallory following a 6-5 season. Never mind that in the previous three seasons his teams had been 9-3, 8-4, 7-3-1. Yet a couple of years after Mallory was gone, 6-5 didn't look so bad, after all. Colorado hired Fairbanks, the former NFL coach. He brought with him a pro-style pass offense that never caught on, and from 1979 to '81 the Buffs went 3-8, 1-10, 3-8. Bye-bye, Chuck.

Hello, McCartney - or Mac, as he is called - an assistant to Schembechler at Michigan for eight years. After a slow start - 2-8-1, 4-7, 1-10 - McCartney bagged Fairbanks' offense and brought in the wishbone - this while the rest of the football world was converting to the pass. "The media ridiculed him for that," says a CU spokesman. But the following year, the Buffs went 7-5 and landed a Freedom bowl berth - their first bowl in eight years. In three of the last four years, the Buffaloes have won a bowl berth.

"The next three years we have to establish ourselves as a Top 20 team," said McCartney at the start of the '88 season. In the final regular-season poll the Buffaloes were ranked 20th. Prior to this season they hadn't been ranked since 1978.

The CU program appears to be on solid ground, largely because McCartney, resisting the urge to panic, built the program gradually and patiently, with freshmen recruits. The current team includes 13 regulars from the recruiting class of 1986, and four more from 1987. There might be more, but many recruits have been lost along the way.

According to Dave Plati, the school's sports information director, the Buffaloes have had a bad local reputation for a series of off-the-field incidents during the last three years. McCartney seems bent on changing it.

Just in the past year alone, he has dismissed two former starting fullbacks - Anthony Weatherspoon and Michael Simmons - plus cornerback Anthony Harvey, for one year; suspended defensive tackle Cole Hayes, safety Sam Sutherland and Aunese for all or part of spring practice; suspended six offensive linemen for part of fall camp.

For a time, it was believed he would suspend nine more players for the Freedom Bowl, but he didn't. All this is to say nothing of what McCartney has done in past years (in '85, for instance, he suspended four players for one year). McCartney's punishments were dished out for everything from public brawling to breaking into equipment sheds and "violation of the team's alcohol ban."

Nevertheless, the coach says, "The kinds of things that have been happening off the field have given us a reputation that really doesn't portray us accurately. Really we have a clean-cut wholesome bunch of kids, despite what the public might per-ceive."

If there has been anything else that has marked the McCartney era, it has been toying with the offensive scheme, which has become almost an annual occurrence. This he converted the wishbone into a combination bone and power I (or I-bone) to utilize the talents of a couple of halfbacks - namely sophomore Eric Bieniemy and junior J.J. Flannigan.

At 5-foot-6 (and 190 pounds), Bieniemy is fully a foot shorter than a handful of his teammates and many of his rivals. "If I wasn't built this way, I wouldn't be able to take the punishment I'm taking now," he said earlier this season, but the punishment did catch up with him. Bieniemy was the nation's sixth leading rusher, totaling 1,243 yards and 10 touchdowns - despite missing most of the last two games with a hamstring injury. He averaged 124 yards a game and 5.7 yards a carry. When Bieniemy isn't on the field, he's barely missed. Flannigan, a 6-foot, 190-pounder, rushed for 522 yards and six touchdowns and averaged just under six yards a carry.

Aunese, the quarterback, also is a fine runner - he has rushed for nearly 1,000 yards during the past two seasons - but he's a weak passer - he completed just 41.5 percent of his passes for 1,004 yards, two touchdowns and five interceptions. The Buffs attempted only 125 passes all season - and averaged a whopping 23.8 yards per completion. But they live by the run. To wit: junior Jeff Campbell, a second-team All-Big Eight wide receiver, has caught only one touchdown pass in his entire collegiate career - but has scored five touchdowns on the reverse, two of them this year.

The Buffaloes were the seventh best rushing team in the country this year, but often the defense, which started the year with very little experience, was the best part of the team. Playing in Lincoln, the Buffaloes held Nebraska, then the nation's top scoring offense, to seven points. In their last six games they allowed an average of just 11.5 points a game.