Bottom Line
Maintenance Q&A

Paul Abelson
SENIOR technical editor

QuestionI went to fire up the truck, and the fan belt squealed. The alternator belts were loose, so I tightened them. When I took the belts off, it took quite a bit of effort to turn the (alternator) pulley. The alternator still charges good. It is currently going on 3 years old. Could the bearings be going bad?

Answer: It is probably past time to change the alternator. A few years ago, Prestolite showed an alternator at a TMC meeting. It had, if memory serves, more than 750,000 miles. That alternator was most definitely an exception. Most new alternators will give 200,000 to 250,000 miles of service. Rebuilt ones, 150,000.

Noteworthy ...
Every so often, I find a useful repair text or video. This time, it’s a CD I found at the Chicago Auto Show. It’s for those of us who are not motor heads, who know barely more than how to check the oil on a truck or our cars.

For those who need to review the basics of maintenance and repair, to understand what needs done and how easy much of it is, this is simple to understand. It has video sections that demonstrate as they instruct.

Don’t let the title bother you. “Car Care for Women” is for men, too. And except for things like spark plugs, most of the principles apply equally to big rigs.

ASE Certified Master Technician Pete Bilotta produced the CD with its video sections. It’s very well done, and it reminded me of a few things I had forgotten. The CD lists for $19.95, available from Bilotta at 1-800-966-3681 or www.car-care-for-women.com.

Failures used to occur when brushes wore out, but with today’s better materials and brushless designs, bearings, bushings and housing damage are major causes. The clue to an imminent failure was the effort to turn the pulley. If not a bearing failure, something inside the alternator is restricting free movement, or the pulley mounting may no longer be true.

When replacing an alternator, make sure all pulleys are undamaged and running true. Check brackets to be sure they are not bent. Make sure all pulleys line up so the drive belts are not pulled over the edges of the pulleys. It’s a good idea to change drive belts, too. The stiff pulley may have damaged them. It doesn’t take much to glaze the belts’ traction surfaces or start to fray the edges.

If the alternator quits working after you’re asleep on a cold night with a heater running, or a warm one when you have your air conditioner on, you can draw the batteries down enough that the fuel solenoid will not stay on. Then the truck shuts down — not pleasant in mid-winter or mid-summer.

Question: I want to install two work lights on the back of my tractor for more light when I couple/uncouple from trailers, tarp loads, etc. I would like to use the tractor’s power, but if that is not advisable, I could install an inverter. I am just not sure what gauge of wire to use and if I should run the wires directly from the batteries. Also, I would like to install a dash-mounted toggle switch, so I can turn on the lights before exiting the cab. So would I run the wires from the lights to the toggle switch and separate wires from the toggle switch to the power source?

Answer: Basic work lights are nothing more than 4-inch round backup lights mounted on the back walls of tractors. They should be wired with a separate switch so they are not on when the vehicle is in motion.

You can upgrade from the incandescent bulb or sealed lamp to an LED backup lamp or dome light. Current draw is far less. For example, Truck-Lite’s LED Model 44 dome light draws 0.5 amps, compared with 2.1 amps for a No. 1156 bulb or 2.16 amps for a sealed lamp. Truck-Lite’s backup lamps draw 0.25 amps each.

The typical back-of-cab work light setup is designed to illuminate trailer noses during hookup. You mentioned you throw tarps, so it would seem you have a platform trailer, either a flatbed or drop deck. That means you’ll be working farther from the rear of the cab, so you’ll need to throw more light farther out.

I recommend mounting utility lights or even fog lights high on the back of your cab, angled down onto your work area. There are many 12-volt lamps that will work well, so there is no need to use an inverter for this application. With a flatbed, I assume you do not have a high-rise sleeper. Make sure the lamps are below the roofline, so they do not affect tractor aerodynamics to any great degree. The effect is minimal, but with fuel prices as they are, there’s no need to add any drag.

Many work lights designed for snowplows and construction trucks use halogen bulbs that draw 4.6 amps each. For two halogen lamps, the highest total current draw will be 9.2 amps. Figuring a total run of wire from the battery to your dash switch to the lamps at the back of the cab, then back to the battery for a ground, I doubt the total length would exceed 40 feet.

Twelve-gauge wire will be more than adequate if you are using halogen bulbs. Sealed or incandescent lamps will need 16-gauge wire. For the LED lamps, you could probably get away with 20 gauge, but I find it harder to work with and not often useful. Sixteen (16) gauge is the smallest I keep in my toolbox, just because it has more structure to it. Buy multistrand wiring from an auto or truck supply house. Hardware stores carry single strand wire good for household use. It doesn’t have the flexibility needed for vehicle applications.

When you run the wiring, put an appropriate size fuse as close to the battery as is practical. I recommend using a lighted rocker switch; lighted so it will alert you when it’s on, and a rocker rather than a toggle because they don’t hurt as much if you bump them.

It’s always a good idea to take your grounds back to the batteries, preferably with a sealed harness. Chassis grounds are subject to corrosion. With corrosion from road salts, look into harnesses from Grote or Truck-Lite. They have sealed connections designed to resist corrosion.

Never cut into existing wiring to get power. Doing so violates the integrity of the insulation and allows corrosion to migrate inside the wiring. If you must splice wires, use heat-sealing crimp connectors with a length of heat-shrink tubing as a seal over the connections. If that is impractical, you can seal your connections with liquid electrical tape. This brush-on vinyl does a good job sealing out moisture and salts, but unless you have the hand of an artist, the vinyl cures unevenly. If the connection is out of sight, that shouldn’t matter.

I looked up the recommended wire lengths in an excellent reference, “Diagnosis and Troubleshooting of Automotive Electrical, Electronic and Computer Systems.” Prentice-Hall Inc. publishes it. You can find information on lighting by doing a Web search on “truck lights” or look up Grote, Peterson or Truck-Lite on the Web.

Question: I just bought a 1995 Freightliner last week. I drove it just 400 miles, and the clutch went out. I was only 30 miles from home, so I went nice and slow and got the truck home. I got a guy who has done work for me before. He got the clutch out in about five hours. I went down to the parts store and got the easy pedal clutch and the clutch brake. The guys down at the part store said I should get the flywheel turned. The flywheel looks smooth to me and feels that way, too. Should I get it turned?

Answer: I looked at TMC Recommended Practice RP638, “Heavy Duty Clutch Maintenance Guidelines,” and found only advice to “follow manufacturers’ guidelines” for resurfacing flywheels. The posters on the OOIDA Web site’s Maintenance Forum, several of whom are ASE Certified Master Technicians, were unanimous in their recommendations to reface the flywheel. One said to get it done as long as the mechanic had everything apart. Another — based on his assumption that the flywheel is most likely glazed and may be heat checked — advised to do it right the first time. Cut corners, and it will come back to bite you.

QuestionIt’s time to re-bush my Neway air-ride suspension. Where can I find someone who is experienced with these? I asked my truck dealer, and he struck fear in my heart with the look I got when I asked about it.

Answer: If you’re going to re-bush, why not upgrade to polyurethane bushings? They last longer, resist distortion and improve truck stability compared with rubber. Energy Suspension and Atro Engineering are the leading aftermarket suppliers, but you’ll probably find others on the Web.

The Service Specialists Association — (330) 725-7160, www.truckservice.org — is the national trade association for suspension repair shops. SSA should help you find a good shop in your area.

Paul Abelson can be reached at truckwriter@anet.com.