It was a single page, in Earl's handwriting. It said where the assembly had come from, which revision it was, what had been replaced inside it, and what the test results had been, hour by hour. At the bottom, it explained, in plain language, what had gone wrong with the first one and why.
Carl read it twice. Then he folded it and put it in his shirt pocket.
"You didn't have to write all this down," he said.
"Yes, I did," said Earl. "I should have done it the first time."
Carl looked at him for a long moment, and then he laughed, a short, surprised bark.
"You know what? I'll take that over a warranty card any day." He held out his hand. "We're square, Earl. And next time I need something, I'm calling you first."
---
But Earl was not square with himself, and on the drive home he told Ray what he wanted to do.
"Every part," he said. "Every part that leaves this place. I want to know exactly what it is. Not the family. Not the model. The exact generation, the exact revision. I want to know which tractor it came from, that tractor's serial number and build year. I want to know what's inside it and what we replaced. I want it checked against the service specs, not just against the housing. And I want it tested like it's going to be used, not just to see if it leaks."
"That's a lot of record-keeping, Dad."
"It is."
"You can't keep all that in a pocket notebook."
"No," Earl agreed. "I can't."
They both thought of the same person at the same time.
---
Megan built the system over three weekends at the kitchen table, with Earl sitting across from her and answering questions until he was hoarse.