Question: I am looking for information on what I define as "performance indicators" in the area of school bus maintenance. How can we measure if our operation is efficient and maximize the use of our resources? Are there some predetermined "performance indicators" that I could use? For example, the number of mechanics per bus, number of bays per bus, cost of repair by units, replacement schedule, etc. from jeanpb@gov.nb.ca via e-mail.

Dick Fischer: The easiest way to tell if your operation is efficient is by noting the driver defect reports (DDR). It is demand maintenance vs. good maintenance. If you have five DDRs in one day and you only fix two of them, then you're going to have eight the following day and that's inefficient. Also, check the safety schedule required by your state. Most states require school buses to be inspected every 30-45 days. My recommendation is do it every 30 days. Regarding mechanics and bays, there should be 15 mechanics used per bus, and one bay per mechanic. You should also have a couple of extra bays for major repairs. Another thing you need to look at is if all of your technicians are working day shifts. If that's the case, then not much work is being done because everything is on the road.

Question: I am working on a 1984 Ward/Ford school bus with an 8.2N DDA engine, air brakes, auto transmission. The problem I am having is with the electrical system. I keep getting a fluctuation in the voltage. I have replaced/checked the alternator, regulator, batteries, wiring to these components, etc. but cannot locate the problem. The fluctuation is very evident when driving with the lights on for fog, darkness, etc. Fluctuation of 1.5-2 volts. Any suggestions? From Jack Hellbusch.

Dick Fischer: It is too small of an alternator for the output. It's only a 60-amp alternator and there's a draw of 80-90 amps. That's why everything goes out. We put in a 100-amp alternator and changed the wirings and don't have any problems with it. To test, you have to turn everything on and take an amp reading, that will tell you how powerful an alternator you'll need. You need one that generates 10 percent above what you're drawing so you can recharge the battery. Check the amperage draw with engine idling and at 1,500 rpm.

Source: School Bus Technician, May, 1999