Bates and co-driver John McCarthy overcame rough roads and unexpected heavy rain to finish almost 90 seconds ahead of Subaru’s Molly Taylor, with Mitsubishi’s Mick Patton third overall.
He now leads the series from Taylor by 195 to 192 points after the third of five rounds in this year’s championship.
Bates led the event from the start, only relinquishing top spot once to Taylor after the second stage. Regaining the lead in stage three, Bates was not headed again. He claimed seven of the 13 completed special stages – a total of 212km of competitive driving – to secure a bonus point for the most stage wins.
Autumn sunshine greeted competitors for Heat 1 on Saturday, with Bates winning five of the day’s eight special stages to beat previous series leader Nathan Quinn (Mitsubishi) by 16.3 seconds, with Taylor third.
Bucketing rain provided a new challenge as the rally moved into the Brindabella Mountains for Heat 2, with conditions forcing organisers to cancel the penultimate stage.
The win was particularly satisfactory given the testing conditions, with wet weather forcing the cancellation of Special Stage 13, but also in light of the problems that affected Bates’ S2000-spec Toyota Corolla in the previous round in Western Australia.
“We all worked really hard in the preparation; the guys in the workshop as well as John and I studying the videos of last year’s event,” he said.
“The roads were especially rough this year; a number of crews suffered suspension problems, but our Corolla with Toyota Genuine Parts was strong to the end.
“We overcame an early problem on Saturday to win three stages in a row in the afternoon, building a 16-second lead, so we were very happy.
“On Sunday morning, rain in the Brindabella’s was a real challenge, a balancing act between protecting the rally lead and not being too conservative or losing concentration.”
The National Capital Rally also saw Harry’s brother Lewis and his father Neal, a four-time ARC title-holder, competing in different classes.
Lewis Bates (Toyota Corolla) was forced to retire while Neal Bates and co-driver Coral Taylor, in their Toyota Celica RA40, won 11 of the 13 special stages in the Classic category.
However, a wheel alignment problem on Saturday afternoon cost them any hope of an overall victory.
Round four of the national championship will be held in South Australia’s Barossa Valley from September 15-17.