Jim Booth, an application engineer in the Cat On-Highway Truck group and an experienced truck driver, shares his thoughts on pre-trip inspections:

As a truck driver, one of my least favorite things is sitting around waiting to load or unload or, even worse, waiting on truck repairs. While there’s not much drivers can do to lessen loading times, we can play a big role in minimizing the time spent on repairs. The trick is performing a thorough pre-trip inspection every day—one that can detect potential issues before they become real problems and create unwanted downtime. Here’s the checklist I follow for a meticulous pre-trip inspection (yours may vary slightly depending on state requirements):

• Make sure you have the right tools on hand—a flashlight, hammer (3 lb. is good), tire air pressure gauge, gloves, shop rag and wheel chocks are necessities.
• Start by placing wheel chocks on the front and back side of one drive tire, which will keep the truck from rolling when the brakes are released.
• Open the hood and check all fluid levels—engine oil, power steering fluid, windshield washer fluid and coolant. Look for oil or coolant leaks, which could be caused by something as simple as a loose hose clamp and easily repaired. Check coolant hoses, power steering hoses, air conditioning hoses and electrical connections. If you find a hose rubbing against something, like a bracket, fix it before it wears a hole by adding a protective wrap or relocating the hose. Also check the fan belt.
• While the hood is open, inspect the front brake air lines, brake linings and brake drum. The Department of Transportation (DOT) has minimum requirements for brake lining thickness, and it varies depending on the type of brakes or brake system. For the most part, if brake linings are less than 1/4″, it’s probably time to replace the brakes. Look at the front springs for any cracks or broken leaf springs. Make sure the spring u-bolts are tight and not broken.
• Inspect the front tires, checking side walls for nicks or cuts and tread depth. DOT requirements for steer tires are a minimum tread depth of at least 4/32”. Look at the rims for cracks or dents. Make sure all the lug nuts are there and tight. Check the axle seal area for oil leaks. When comfortable with the front tires and everything under the hood, close the hood and secure it.
• Start the engine or turn on all the lights and flashers (four ways) before beginning your walkaround. If your truck has a hand brake valve that stays on when applied, use it to check brake lights. Otherwise you’ll need a buddy to check them.
• When starting the engine, check the gauges for engine oil pressure and make sure that air pressure is climbing. Low air pressure should activate an annoying buzzer. If the air pressure is low when the engine starts, that could indicate an air leak somewhere.
• If you’ve never driven this truck before, check the cab for any necessary permits, an insurance card and required safety equipment like a fire extinguisher and reflective triangles or flares.
• During your walkaround, check tire air pressure, ideally with an air pressure gauge. If that’s not possible, bump the tires with a short-handled hammer. (Personally, I don’t believe tire irons or tire thumpers bounce off the tire enough to tell me if the tire pressure is good. A heavier hammer bounces off the tire nicely when air pressure is good and has very little bounce when air pressure is low. It also gives you a better comparison of air pressure differences between the two tires of a dual.) Inspect the condition of all tires, including side wall condition and tread depth. DOT requirements for any tires other than steer axle tires are at least 2/32” tread depth.
• Look under the rear axles of the truck (and trailer if pulling one). Check the condition of brake shoes (don’t forget the brake lining requirements), brake drums, air hoses, slack adjusters and brake chambers. Use a flashlight if necessary. Check wheels for cracks or dents. Make sure all lug nuts are there and tight. Check the axle seal area for oil leaks.
• If you’re pulling a trailer, check the condition of trailer air lines. Make sure they’re not rubbing on anything like the deck plate and won’t snag on anything when turning. Check the glad hands to verify they’re tight and not leaking air. Make sure the trailer king pin is locked in the fifth wheel. Get down under the trailer and shine a flashlight into the fifth wheel to see if the jaws are actually clamped around the king pin. Be sure the landing gear is up and the dolly crank handle is secured and not swinging freely.
• As you walk around your truck/trailer, check all clearance lights, parking lights, headlights, brake lights and turn signals. Wipe off all grimy lights for better visibility. Verify the fuel cap is tight on the fuel tank. Check all glass, including mirrors, for cracks or anything else that may affect visibility. Make sure mud flaps and license plates are attached and secured. Listen for air leaks and look around for anything abnormal.
• Once you’re back in the cab, shut the engine off. Turn the ignition key back on and release the parking brakes. Pump the service brakes repeatedly until the air pressure leaks down to below 60 psi. At 60 psi the low air pressure buzzer should activate. Below 60 psi the parking brake and trailer brakes should apply themselves.

With that, your pre-trip inspection is complete and you’re ready for work. (Don’t forget to remove the wheel chocks!) Throughout the day, anytime you’re stopped and waiting, give your truck a quick walkaround. It’s a great way to find and fix any minor issues before they become major problems.