Inspecting a used truck

By Overdrive Staff

A thorough pretrip inspection can uncover obvious problems, such as oil and water leaks, faulty lights and loose belts. The tips here, which include some pretrip basics, give further pointers on assessing a truck’s condition.


1. EXAMINE FRAME for cracks, welds or bends. Rust bleeding from bolt holes indicates loose bolts.

2. LOOK FOR CRACKS and signs of deformity or attempted repairs on the wheels. Rust around lug nuts indicates slippage.

3. RUN YOUR HAND ALONG THE BODY PANELS to check for proper fit. If the surface feels inconsistent, try attaching a magnet to check for plastic body fillers. Surface rust indicates that structural integrity may be compromised.

4. OPEN AND CLOSE DOORS to make sure they seat, latch and lock properly. Run your hand along the bottom of the doors to check for jagged or rusty edges. Check condition of the gaskets.

5. CHECK WINDOWS FOR SMOOTH OPERATION. Inspect the track felt. If an owner didn’t bother to fix a window, there’s a good chance overall maintenance hasn’t been up to par.

6. LOOK FOR CRACKS, chips and pitting on the windshield.

7. CHECK WIRING AND HOSES for cracks, loose connections and corrosion. Firewall insulation should be secure.

8. CHECK THE EXHAUST SYSTEM for cracks and corrosion. Mounts should be secure. Fittings should be tight and well-sealed. Exhaust streaks around fittings indicate leaks.

9. EXAMINE FUEL TANK STRAPS and gaskets for wear and slippage. Check tank itself for wear and leaks. Crossover line, if installed, should be free of fraying and cuts. Shutoff valves should operate smoothly.


11. INSIDE THE CAB, listen for leaks in brake valves. Check seat operation. Make sure drawers, doors and appliances work well.

12. CHECK TRAILER SERVICE LINES and gladhand connectors for damage and leaks.

13. NOTE WEAR IN RIVET AREAS and mounting brackets of sleeper and cab exterior.

14. ENSURE LIGHTS WORK in all federally required positions and are the correct color. Examine headlight housings for rust and general condition.

15. CHECK TIRES FOR SCUFFING and “river wear,” signs of misaligned axles and other irregular wear. Check inner and outer sidewalls for damage. Look for multiple branding marks on sidewalls, which indicate recapping. Check for proper tread depth.

16. IDEALLY, DRIVE TIRES ARE IDENTICAL and made by the same manufacturer; they should at least be the same size. A tire from a different manufacturer is a red flag that the tires aren’t being replaced on the same cycle.

17. CHECK THE RADIATOR for bent, missing or plugged fins. Look for signs of oil or fuel in water, which could signify leaking injector sleeves. Make sure connections are free of corrosion. If fluid color seems off, the engine probably overheats regularly.

18. CHECK FIFTH WHEEL LOCK by stretching truck and trailer.


20. WATCH FOR UNEVEN STEERING TIRE WEAR, which can signify alignment or front-end problems.

21. JACK UP THE FRONT AXLE and shake the tops of tires sideways to check for kingpin and wheel bearing play.




24. CHECK LEAF SPRINGS AND FRONT SUSPENSION for cracks and wear. Watch the suspension as the truck is driven slowly across an uneven surface. It should move smoothly and respond quickly. Air springs should have no cuts, gouges or audible leaks.

25. CHECK BRAKE LINING. Lining must be no thinner than 1/4 inch. Oily stains on the shoes indicate a previously failed wheel seal and potentially oil-soaked linings.

26. FEEL INSIDE THE BRAKE DRUM, if so equipped, to determine wear. With the brakes released, tap each drum with a piece of metal to see if it’s cracked. Check for corrosion, wheel seal leaks and cracked friction material.

27. LISTEN FOR LEAKS IN THE AIR LINES and brake canisters while someone applies the brakes. Watch the amount of pushrod travel to determine if the automatic slack adjusters are working. Make sure all linkage hardware is present.

28. WITH THE BRAKES RELEASED, firmly shake the S-camshaft to determine bearing wear.


30. LOOK FOR HUB LUBE on the inside of wheels, which indicates a failed wheel seal.


DRAIN AIR TANKS AND LOOK FOR OIL, which can indicate that the compressor should be replaced.

CHECK FOR LEAKS in the fuel lines and fittings between the pump and injectors.

LOOK INSIDE THE OIL FILLER TUBE for a milky white substance, which indicates condensed water vapor.

INSPECT DIESEL PARTICULATE FILTER for cracking and breakage. Test the diesel oxidation catalyst by forcing a regen. If the temperature difference between the two DOC sensors is less than 500 degrees during the active regen, it’s probably time the DOC is replaced.

CHECK THE FUEL FILTER FOR BLACKENING, which could indicate oil is mixing with fuel through a leaking injector. Check fuel tanks for the same thing.

IF THE TRUCK HAS DISC BRAKES, check the actuator and caliper, and ensure the pad makes contact with the rotor. Check condition of the rotor.

IF YOU HEAR ANY STRANGE NOISES after the engine has been running for five to 10 minutes, inspect all electrical lines for abrasions and chaffing. All connections should be secure and corrosion-free.

ASK ABOUT AN ENGINE OVERHAUL if the truck’s mileage is 500,000 miles or more. If one hasn’t yet been performed, it’s almost time.

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