How to properly perform a pre-trip inspection on a straight truck with airbrakes.
A proper pre-trip inspection will save time, money, and frustration by reducing maintenance costs, equipment down-time, mechanical breakdowns, and ensuring that your vehicle is safe to operate.
Before you begin and as you approach the truck
1. Consult the truck’s owner manual for the locations of all dipsticks, engine compartment configuration, and any other pertinent information.
2. As you walk up to the truck, look for any fluid leaks underneath the truck, look for any damage to the truck, and check to see if the truck is leaning which could mean there might be a problem with the tires or the suspension system, if you notice any leaks, damage, or if the truck is leaning, consult a certified mechanic.
Under the hood inspection
1. Open the engine compartment/hood (consult the owner’s manual for instructions on how to do this).
2. With the hood open, check the engine oil, the oil level should be above the add mark on the dipstick and below the full mark. If oil needs to be added, go to 3
3. Add oil to the engine via the oil fill cap until the oil level is above the add mark on the dipstick, wipe the dipstick off using a rag or paper towel and fully re-insert it before reading the dipstick. (consult your owner’s manual for instructions on how to do this) WARNING: Use only the correct engine oil as determined by your owner’s manual (commonly 15w40 in diesel engines)
4. With the hood open, check the coolant level, the level should be above the add mark. If coolant needs to be added go to 3a WARNING: Do not remove the radiator cap when the engine is hot.
5. Warning: Do NOT remove the radiator cap when the engine is hot. Add mixed coolant to the coolant reservoir until it is above the add mark and below the full mark
6. With the hood open, check the serpentine belt, the belt should be free of any cracks or splits, the belt should not have more than a ½ inch of give to it when you press down on it. If the serpentine belt is damaged or loose the truck should not be driven before being checked out by a mechanic.
7. Check the air compressor, make sure it is securely mounted and that you don’t hear any air leaking out of it
8. Check the fan blades, the fan blades should not be contacting anything, all the blades should be intact and undamaged
9. Check the leaf springs in the suspension and make sure they aren’t damaged or misaligned
10. Check the shock absorbers to make sure they aren’t leaking any fluid
11. Check the steering tie rods to make sure they aren’t broken or bent
12. Check the slack adjusters and the brake chambers, make sure the air hoses are secured and that the brake chamber and slack adjuster are perpendicular to each other
13. Close the hood and secure all latches
Inside the cab
1. Turn on the fuel pump if your vehicle is so equipped according to your owner’s manual
2. Insert the appropriate key into the ignition
3. Turn the key clockwise into the “RUN” position. Caution: Do not turn the key to the “START” position
4. Wait for the “Warn Engine” light to go off, the engine is now ready to be started (actual wording may vary, consult your owner’s manual for clarification)
5. Turn the key clockwise to the “START” position and hold it there until the engine starts, if engine does not fire, go to step 6
6. If your engine is so equipped, press the ether button located on the dash when the key is in the “START” position WARNING: Do not use ether in engines equipped with glow plugs!
7. If your engine is equipped with glow plugs, check to make sure that the glow plugs, battery, and starter are functioning properly and try again.
8. Check all the gauges, the oil pressure gauge should read between 20 and 60 psi
9. The voltmeter should read between 12 and 14 volts
10. The temperature gauge should be rising and approaching the normal operating temperature for your engine
11. The air pressure gauge should be rising which indicates the air tanks are charging
12. Turn on your headlights and hazard lights, step outside the truck and make sure none of your lights are burnt out and that all of the running lights are functioning properly
13. Turn on your left turn signal, step outside and ensure that your left turn signal is functioning, repeat this procedure for the right turn signal
14. You are now ready to perform an air brake check
Performing an air brake check
1. Ensure that the air tanks are charged above 100 psi, if not, raise the engine speed by placing your foot on the accelerator to speed up the process WARNING: If the tanks are not charging, do not drive the truck
2. When the tanks are above 100 psi, place the transmission in gear with the parking brake engaged and gently apply pressure to the accelerator, the truck should not move WARNING: If truck does move, do not drive the truck
3. Turn the engine off and turn the key to the RUN position (do not turn it to the START position)
4. Disengage the parking brake and place your foot on the brake pedal and hold it there for 30 seconds, you should not lose more than 3 psi of air brake pressure
5. Fan the brake by placing your foot on the brake pedal and releasing it repeatedly
5a. The “LOW AIR” warning should come on at 60 psi
5b. The parking brake should “pop” or reengage at 20 psi
6. Restart the engine and allow the tanks to charge
Final walk around and tire check
1. There are two ways to check the tire pressure, using either an air pressure gauge or a “tire thumper” (a baton or club) If you’re using a pressure gauge go to step 2, if you are using a tire thumper go to step 5
2. To use an air pressure gauge, first check the inside of the door for the proper air pressure information
3. Remove the valve stem cover and place the head of the pressure gauge over the head of the valve stem and press down firmly
4. You should not hear any hissing after you press it down, to read the gauge check where the extender comes out to and the highest number you can read is the amount of pressure in your tire
5. To use a tire thumper, grasp the tire thumper and firmly strike the tread of the tire. If you hear a high pitched thump the tires are properly inflated, if you hear a dull thud the tires are under inflated CAUTION: Do not use tire thumpers with radial tires (commonly found on passenger cars)
6. When checking the tires look for nicks, cuts, and bulges in the sidewalls, and that there is at least 2/32 inch of tread on the rear tires and 4/32 inch tread on the front tires
7. Check the rim for any dents or unauthorized welds
8. Make sure the lug nuts are all present and tightened. Check for rust streaks or shiny threads which would indicate that they are loose
9. Make sure there is no oil or grease contamination in the brake drums
10. Make sure the brake drum isn’t damaged or cracked
11. Check the hub oil seal, make sure all the nuts are tightened and that the seal isn’t cracked or there’s oil leaking out
Your truck has been properly pre-tripped and is now ready for the road, remember to buckle up and obey all the traffic laws.