Dunedin area commander Inspector Dave Campbell said brake fluid samples from the Holden Commodore police car that crashed in September 2006, injuring two traffic officers, were analysed by specialists in Auckland last year in a bid to establish whether the police driver was at fault.
The analysis found the brake fluid was discoloured and contained pieces of metal.
The vehicle's rear brake pads were also found to be cracked. However, specialists had not been able to say conclusively the defects could have caused a brake failure.
The police legal team had concluded there was insufficient evidence to establish a prima facie case of careless use of a motor vehicle against the driver.
Insp Campbell said a police examination of the vehicle's brake system raised further concerns when no record could be found that the brake system had been flushed since the car was relatively new, despite a police requirement to change it every time new brake pads were fitted, which had happened at least twice.
It also found that the brake fluid and rear brake pads were not the correct high-specification products required in police cars, as per a New Zealand and Australian standard.
The two officers were injured and the car was written off in the crash after a high-speed pursuit near Momona.
Minutes before the crash, the officers had called off the pursuit, which had allegedly reached speeds of 200kmh in East Taieri.
The officers were looking for the Subaru when their car failed to take a 45kmh left-hand hairpin bend in Miller Rd, between Dunedin International Airport and Outram.
The car left the road and slid across a paddock, before it rolled into a ditch, coming to rest on its roof.
The findings of the local police investigation were taken up at a national level because there had been other incidents with police cars, Insp Campbell said.
Police national adviser for operational policy and standards in road policing support, Insp Rob Morgan, of Wellington, confirmed this week there had been other ‘‘events'' but could not list them off hand.
The concerns were significant enough for police to conduct an audit of their Commodores.
Insp Morgan said the audit found there had been a ‘‘mixup'' and some garages that serviced police cars were not using the correct specification brake fluid or the harder brake pads, although the standard had been upgraded six months before the Momona crash.
As a result, Holden issued a nationwide service bulletin to its dealers last March, identifying the correct parts to be used and the NZ Police fleet management company was reminded that servicing procedures for brakes had to be carried out correctly, Insp Morgan said.
The fleet would be audited again this year to ensure brakes systems had been correctly serviced.
Holden corporate affairs manager Brodie McClellan, from Auckland, said service bulletins were not unusual and were issued regularly, even several times a day.
When dealers were notified of a change in specifications, the parts would generally be changed at the next service.
She could not confirm if dealers had been notified of the new specification brake parts when the upgrade was introduced.
‘‘Holden has confidence our dealers follow the right service procedures while servicing all police vehicles,'' Ms McClellan said.
