The Romance of Preventative Maintenance
Funny how dreams turn into nightmares. My boss was doing me a favor by letting me drive a trip from North Carolina to Colorado, because the group leader was a young lady I was infatuated with.
He'd sent me out in a Scenicruiser whose clutch was only slipping a little in 4th gear. By the time we reached Amarillo.. the dream had become… bad. The bus topped out at 25 in 2nd, as the clutch slipped more and more, and I had to do something.
In ye olden days, if you had a 3/4” wrench and a tad of knowledge (or a mechanic who could coach you on the phone) you could lock a clutch up tight and “ride steel” to make it home.
My relief driver was a studly dude named Dickie, and while I wallowed under the bus, he hung out with the group leader. I emerged from the pit triumphant, but covered with grease, expecting to bask in glory. Instead she said “How come you're so dirty… and Dickie always looks great?”
Some failures are predictable. In this case, both my romance and the clutch were doomed, a savvy soul would have seen both coming.
Mechanical stuff has a finite life, and often it's predictable. It's neat to yank a part out of a bus 15 minutes before it would have failed. It's also good economics.
Sometimes a kindly coach would give you a hint… if an 8V71 burned a quart of oil every 100 miles.. time to consider retiring it. If a bus's backup lights didn't torch off until you revved the engine in reverse… the automatic transmission was ready to fail. Belts squeal, power steering pumps whine.. you get it.
Airlines often replace a component based on its’ projected life. If a wing-nut normally lasts 1,000 hours.. sticking a new one in at 950 hours makes sense. (Hate it when your wing-nut falls off)
We probably should do this type maintenance in the coach industry, but usually don't.
One reason is that we aren't good at analyzing failures.. and predicting them. Another is that parts suppliers aren't always forthcoming with life cycle projections.
An engine warranty might be 200,000 miles… but we rightfully expect lots more. How MUCH more is the question.
One alternator supplier offered a lengthy warranty, but only if you changed bearings every 50,000 miles. The bearings lasted substantially longer, but the manufacturer was unable (or unwilling) to say HOW long, and protected itself with the 50,000 mile mandate.
Many modern components last longer than in the past, but give less warning of failure. Brush-less motors seem to fit that description.
One thing we, as an industry, could do is improve on our ability to analyze and share information. We know (or think we know) lots of things anecdotally. It would be nice to consolidate hard facts. How long does an AC compressor usually last? How many miles can one hope for in a transmission. Are there warning signs when a wheel bearing is going to go out in a blaze of glory?
Aftermarket parts suppliers do some of this sort of analysis to control inventory. It would be nice if we had access, in general terms, to their insights. Great Big Buslines (GBB's) do a lot of it… which brings us to another area where we, as an industry, could use some help.
GBB's study the life cycle of parts, and fashion maintenance schedules accordingly… but when a component is altered, or newly introduced… they sometimes find it hard to get manufacturers to project its expected life.
A widget builder is reluctant to say their product will last, on average, 200,000 miles… because then everyone will expect EVERY widget to make that number. They also don't want to only claim 20 miles, because then nobody would buy them.
It would be nice if we could get them to offer a reasonable prediction.. a mileage where we should consider replacing it. It's a safe bet that the widget folks gave the coach builder some idea of what to expect… why can't we know that number?
Warranty is different… we should expect the vast majority of any component to long outlive its warranty… but manufacturers must have SOME idea how long their part will last in the real world past the warranty.
We “rode steel” from Amarillo to our Colorado destination… to add insult to injury, Dickie didn't have the finesse needed to drive a coach whose clutch could not be disengaged… so he sat with... MY group leader... for all 400 of the remaining miles.
My boss was certainly well intentioned in assigning me the trip… but chalk this one up to “no good deed goes unpunished”.
Wonder what would have happened if we'd gotten that clutch replaced before it failed...
