He led going into the first turn and was never headed for the rest of the final.
'Jared Fletcher (8M) challenged me hard about halfway through but I managed to pull a gap towards the end of the race and won pretty comfortably,' Ethan said.
His brake issues started in the shootout.
'I lost them in my race with Daniel. We managed to get the front brakes back before the final but I lost them again about halfway in.'
Cook said they use their brakes a lot to turn their cars into the corners, so that made it a struggle for him to stay in front.
'I just had to adapt and learn quickly to drive the car without them,' he said.
'I had to ease off a lot earlier and let the car slow a bit before the corners, so it was a hard race, hard work.
'But it was awesome to win it.'
There was one caution break in the final when a car from Stratford hit the wall in Turn 1. The driver was OK.
Daniel Cook finished fourth in the final behind cars from Mount Maunganui and Auckland.
Ethan smashed the lap record for saloons during the heats.
'I managed to take 0.8 of a second off, and got round the track in 14 seconds flat,' he said.
'I couldn't believe it when I saw the time. I was rapt.'
The next race in the five-event V8 series will be at Meeanee in Hawke's Bay this weekend.
Gisborne Speedway Club president Clyde McGrory said the saloon racing was the highlight on Saturday night.
'It was fantastic racing from the 15 cars, and well done to Ethan and Daniel Cook.'
Clive Ireland and his swinger Chris Symon (56G) teamed up with Stu Priest and Kerwin Arnaboldi to win the Ireland Motors Best Pairs title.
'The sidecars were really good,' McGrory said.
Rob Miller and Red George (8P) combined with an Auckland combination to finish runners-up.
James Clarke (16G) had a barnstorming night in the stockcars with three wins, and he took out the Sam's Upholstery Services Stockcar Classic.
Clarke's duel with Ben Holt 4G) in Heat 2 was one of the races of the night as the pair fought their way round the track. The lead changed hands a couple of times.
Holt almost pipped him on the line and Clarke got there by not much more than a coat of paint.
Clinton Cheetham in 361K was runner-up in the Classic and Holt was third.
The Eastland Oil and Engineering and Simpson Automotive Ministock Best Pairs winners were Seth McKay (48G) and Henry Steel (61B). Ethan Bruce (84G) and his partner finished third.
Anton McKay (17V) was in fine form in the production saloons with two wins. Lloyd Stuart (34G) had a win, too.
Gisborne's John Taylor (7G) and Reece Jordan (73G) raced well in the TQ midgets, and Jordan won the feature.
The places were shared around in the streetstocks, with wins to Cody Gooch (6G), David Hampton (88G) and Brenden Gooch (2NZ).
' At the Palmerston North track at the weekend, Peter Rees (2NZ) finished runner-up in the New Zealand Superstocks Grand Prix.
He was rapt to do so well, particularly given the amount of attention he got from other drivers.
The Gisborne Speedway Club's next meeting on December 21 will feature the Burger King Pro Dirt Super Saloon Series.