THERE is a moment in the 1975 Grand Final between North Melbourne and the Hawks that brings Ron Barassi's passion theatrically into conflict with a much-loved local custom.

A documentary crew had access to Barassi and his Hawthorn counterpart John Kennedy, access that included the coaches wearing microphones.

The documentary was never made, but film and audio of the day have been dug up from AFL Archives and form the basis of the 1975 instalment of The Final Story - the three-part documentary on three epic Grand Finals

The other episodes are based around the 1984 and '90 Grand Finals.

WEG posters of the premiership team were an indelible part of Grand Final day in Melbourne for several decades. Before the 1975 Grand Final, Barassi is shown ripping up a poster depicting a North Melbourne victory.

Barassi is warning against the fate of the posters in the event of a North Melbourne loss. "If it happens, they get shredded," he bawls.

Also in the documentary, Kennedy is shown at half-time giving his famous "Don't think, do" speech. As the Kangaroos kick away during the second half, he laments from the coach's bench that the game is slipping away.

The 1975 Grand Final had so many subplots. The Hawks were raging favourites. The Roos were going for their first premiership.

The two coaches, Barassi and Kenendy, were titans of the game. Characters like Roos pair Sam Kekovich and Mick Nolan were larger than life.

Documentary-maker Peter Dickson, who wrote and produced the 1975 and '90 episodes, collated footage from Channel Seven, the ABC and the AFL archives as well as radio calls from various stations.

Over recent months, he's shot interviews with a dozen players and coaches from both teams before piecing it all together for the documentary that will go to air on Channel Seven on Sunday, September 9.

The 1984 and 1990 documentaries will screen on the subsequent Sundays, September 16 and 23.

Dickson said he tried to make the documentaries appealing to non-football people. "The 1975 Grand Final is just a rollicking tale," he said.

Both Dickson and his fellow documentary-maker Wayne Dyer, who wrote and produced the 1984 episode, said the former players were able to open up — even players from the losing teams — because there was sufficient distance between the game and the present.

It's the players' candid observations that lend power and poignancy to the three installations of The Final Story.

AFL chief operating officer Gillon McLachlan said: "The insight and emotion captured in these documentaries makes them a must see for everyone, regardless of whether or not you're a fan of Australian football.

"All three documentaries are of the highest quality."

The Final Story - 1975 will air on Sunday, 9 September, at 11.30am local time on Channel 7 and at the same time on 7mate in New South Wales and Queensland