His passenger jumped from the moving vehicle, severely injuring his ankle in the process.
Donald Robbie, 80, of Otapawa Station in Tiraumea, was driving the farm truck laden with 4.5cu m of gravel down a track on a steep hill on Tuesday when he went to use the foot-brake.
"The brake just went to the floor, I pumped it and nothing."
Mr Robbie's sons and contractors working on the farm at the bottom of the hill watched in horror as the Isuzu truck began to pick up speed.
"They saw me going around the hill face, getting faster and faster. There was nothing anybody could do," he said.
His passenger Colin Howes, a contractor in his 60s from Pahiatua, jumped from the cab.
"As the truck gradually sped up, he thought that was the best avenue of escape."
Thinking quickly, Mr Robbie managed to ride out the drama for half a kilometre, keeping some control over the vehicle by using a drain beside the track for resistance.
"Your thinking goes into overdrive, trying to think ahead about where you're going to end up. I was in the drain all the way, thinking that would help it slow down.
"I managed to keep it on the track then, when I got down to the flat, I was able to point it up."
At the bottom, the truck jumped over a culvert, landing upright, and he turned into the bank of a hill, eventually coming to a standstill.
"I was airborne for a little while," he said.
Mr Robbie said he was thankful to finally come to a stop.
"I sat for a moment and thought someone's looking after me."
Mr Robbie got out of the truck and walked back up the hill, worried about Mr Howes.
"He wrecked his ankle, the spinning motion of hitting the hard ground. He was quite composed, he just sat there and talked.
"He thought the earlier, the better [to jump]."
Mr Robbie's wife Marlene, who had just come back from a trip to Pahiatua, arrived at the farm to see emergency services at the scene.
"I just felt sick," she said.
She said the people who witnessed the incident said it was terrifying to watch.
"They said to me they thought they would have been taking out a corpse."
She said her husband, who has been a farmer all his life, had been in a few accidents before and was like a cat with nine lives. "I think I'm running out of them," said Mr Robbie.
Both men were flown by the Philips Search and Rescue Trust helicopter to Palmerston North Hospital, where Mr Howes had surgery yesterday.
Mr Robbie was left with a hairline fracture in his neck and a suspected lumbar injury, and said it could have been a lot worse.
The Robbies said they planned to build an emergency arrest on the track because of what had happened.
By Vomle Springford of the Wairarapa Times-Age
