By Dave Millhouser
Ouch. Our boss had found another “deal,” and experience had taught us that his bargains were often costly.
Our 4106 needed an engine, and Joe found a Detroit Diesel in a salvage yard, a truck pullout. After stuffing that jewel into the ’06 and firing it up, off he went—backwards. Four speeds in reverse and one forward. Gee whiz, who knew that an 8V71 would happily turn in either direction, depending on which camshafts and idler gear it had? Trucks like right hand, but GM buses demanded a lefty.
We once bolted a used differential pumpkin in a Silversides. Apparently, the ratio was slightly different than the original, because that puppy went fast enough to make Chuck Yeager flinch.
Just because something fits doesn’t mean it’s right. Coaches have a long service life and as they age, providing parts can become a challenge.
In ye olden days, the science was in knowing which parts to stock and how many to have on the shelf. You could count on wearing out brakes, so you stocked a lot. You tied up as few dollars as possible on items that were not critical, or rarely used.
A rule of thumb was that parts in your inventory for more than a year had doubled in “cost.” Between obsolescence, damage and inventory shrinkage, stocking parts costs a bunch more than the acquisition price. A savvy buyer can cut your inventory cost; you can use that “found” capital to buy a revenue generating bus.
Modern transportation and computerized ordering have changed things. Parts are available quickly, and your supplier often acts as your parts room. The trick is balancing shipping costs, risk of a coach sitting and volume discounts. Some parts are seasonal… AC-related parts in spring is obvious, but salty winters wreak havoc on bellows, too. You may want them in inventory in spring, then trust your supplier the rest of the year.
One thing that hasn’t changed is the need for good parts people. The job has evolved, but not the urgency. Good ones still buy the right parts at the right time in the right quantity… from the right vendor.
The best still have a feel for parts that interchange between makes and models of buses. A 4104 bellow worked great on an MC9, and 2316669 was the windshield part number for at least five models of GM coaches.
Just because it fits doesn’t mean it’s right. In 2001 my employer sent a bunch of engineers and service folks to Dallas to test buses for harmonic vibrations. We were experiencing shaking, and we wanted to see if competitor coaches had similar problems. We rented every model of 45-foot bus available and charged around a nasty 20-mile course.
All but one did pretty well. This model had a reputation for superior suspension, but the coach we tested rode like a rock. Body organs were shaken loose, and several of us burst into tears.
An engineer figured it out. The rear bellows assemblies were wrong. They “bolted up,” but the piston was for a heavier coach and stiffened the ride. The parts folks were fooled because they looked similar.
The steering box in our old jeep had croaked and our parts guy found a used one in the junk yard. It looked odd, mounted on the front of the axle, because the original was on the back. It bolted up though, and what could go wrong? Maybe a freaking jeep that went left when you turned the steering wheel right!
There’s no substitute for a savvy parts person, but a bad one can really hurt you.
