One Tuesday in May
One Tuesday in May 2024, a white pickup truck pulled into our yard with the first box of parts for what we thought was going to be a routine Liebherr D936 general overhaul. The mechanic opened the tailgate, looked at the label, and asked, “So how many rings does Rose have?”
Rose isn't a person. Rose is the name we gave our Liebherr crawler excavator. And the mechanic wasn't asking about jewelry. He meant the piston rings in the D936. I didn't have an answer. That's how this whole thing started.
I've been procurement manager for a 140-person earthmoving contractor for about six years. I manage a parts and service budget that usually lands between $500,000 and $600,000 a year. I've negotiated with more vendors than I can count, and I've built enough spreadsheets to know that the cheapest quote is not the cheapest quote once you count downtime. But knowing that and acting like it are two different things.
The track sag I ignored
Back in March, Rose started getting noisy. The left track sagged more than it should. One operator said the machine pulled right. Another said he'd drive it to the end of his shift and decide later. We had a Liebherr D936 general overhaul already planned for May, so I told myself the undercarriage could wait. We had budget for the engine work. We didn't have budget for a whole new undercarriage.
That was my first mistake.
We didn't have a formal track inspection process. Nobody was measuring pin wear or track tension. We just looked at the machine and figured “it's still moving, so it's fine.” That's the kind of thinking that gets you an emergency air freight bill later.
The D936 was the easy part
When the D936 overhaul started, the engine turned out to be in reasonable shape. Some piston wear, a few gaskets that needed replacing, but nothing that told me we should have done the job earlier. Ed, the mechanic, tore the engine down and got to the point where he needed ring sets. That's when he asked about Rose.
“How many rings does Rose have?”
I thought he was joking. I had no idea. The D936 is a six-cylinder engine, and I later learned that each piston runs three rings—two compression, one oil—so Rose has eighteen piston rings. But at that moment, I couldn't answer a basic question about an engine we were overhauling.
The engine wasn't the real problem, though. While we had the machine up, Ed walked under the track and came back with a look that meant money. “You're going to want to see this.”
The track links were stretched. The pins were worn. One roller was leaking grease. The sprocket teeth had sharpened edges that should have been caught months earlier.
“You're going to pay for those parts either way,” Ed said. “The only question is whether you pay the freight now or pay the downtime later.”
The undercarriage quote hunt
The distributor's portal had a line item that read “General overhaul Liebherr D936” and a separate section for undercarriage components. In my first draft of the quote, I checked the engine parts and ignored the undercarriage. That was my second mistake.
Once I started calling around for Liebherr undercarriage components, I found out how naive that was. Nobody keeps a full set of track links, pins, bushings, rollers, and sprockets sitting on a shelf. One vendor quoted a complete set at 12 weeks. Another said 10 weeks. A broker had partial stock, but when I asked where the rest would come from, he said “we can get it” without a real date. The one supplier who actually had the parts in hand could air-freight everything in five days. Their quote was about $5,800 higher than the cheapest real quote. These figures came from our own quote process in May 2024, not from a market survey. Verify current pricing and lead times with your local dealer before you bet a machine schedule on them.
I almost told him to wait. Then I ran the numbers. Rose bills around $12,000 a week on the site she was working. If we waited 10 weeks instead of five days, the machine sat for nine extra weeks. That's $108,000 in lost billing before you even talk about the late penalty. The $5,800 difference wasn't a premium. It was the cheapest option.
What certainty actually costs
I used to think rush charges were just vendors padding margins. Then I spent a week trying to nail down a delivery date that no one could guarantee. The vendor with stock wasn't charging me for speed. They were charging for the fact that they actually had the parts and knew when they'd arrive. That's a different product.
The air freight bill itself was around $4,200. Maybe $4,000. I'd have to check the invoice. But the total difference between the cheapest quote and the one we went with was roughly $5,800 including freight. Worth every dollar.
We paid it. The parts left Europe on Thursday, landed on Saturday, and were on a truck early Monday. (Note to self: never use the old yard address in the delivery fields again.) The machine was back at work nine days after we placed the order. I tagged the invoice in our cost tracking system as rose_undercarriage_2024. Every time I review the annual report, I see the $5,800 premium and remember the $108,000 we didn't lose.
What I'd do differently
The white pickup truck now shows up once a month for track inspections. We measure pin wear, check track tension, and photograph every sprocket. I built a simple checklist after that first inspection, and we now quote Liebherr undercarriage components as part of any major service, not as an afterthought.
Any machine that goes in for major service gets an undercarriage evaluation before the quote is final. It doesn't take long, and it costs nothing compared with what we paid.
It took me six years and more emergency freight bills than I want to admit to understand that procurement is not about the lowest line item. It's about the lowest cost of getting the machine back to work. If we had caught the undercarriage wear in March, we could have ordered the parts at normal lead times and had them sitting in the parts room before the D936 overhaul started.
So, how many rings does Rose have?
Eighteen, if I remember correctly. The Liebherr D936 is a six-cylinder engine, and each piston uses three rings—two compression rings and one oil ring. Don't quote me on the exact count; I'd have to check the manual again. According to the Liebherr D936 service manual, ring sets are specified by engine serial number, not just the model. The manual is the authority. My memory is not.
Would I pay a rush premium again? If the cost of being late is higher than the cost of being certain, I'd pay it today. Not because I like the line item. Because I know what “maybe” costs. In this business, certainty isn't a luxury. It's a procurement strategy.