Truck maintenance can be viewed as maintaining a complex "ecosystem" comprised of several major systems: the powertrain, drivetrain, chassis, and electrical systems.

1. Core Principles & Safety (The First and Most Important Step!)

1. Safety First:

   • Personal Protective Equipment (PPE): Always wear safety glasses, gloves, and steel-toed boots. Use ear protection and goggles when necessary.

   • Lifting Safety: After jacking up the vehicle, it must be securely supported with jack stands (or axle stands). Never rely solely on a jack.

   • Work with Engine Off: Always turn off the engine, remove the key, and chock the wheels before starting any work.

   • Warning Signs: Place warning triangles or cones a sufficient distance behind the vehicle.

   • Ventilation: Ensure your workspace is well-ventilated, especially when running the engine indoors or using chemicals.

2. Tool Preparation:

   • A good set of metric/imperial combination wrenches, socket wrenches (especially extensions and high-torque sockets), screwdrivers, and pliers.

   • Tire wrench, jack, and jack stands.

   • Diagnostic tools: Multimeter, diagnostic scanner (code reader), tire pressure gauge.

   • Special tools: Depending on the job, you may need pullers, a torque wrench, etc.

3. Information:

   • Obtain and keep the truck's Service Manual. It is your "bible," containing all technical specifications, procedures, and wiring diagrams.

2. Daily Checks & Preventive Maintenance (PM)

This is the most crucial and frequent part of truck maintenance, effectively preventing breakdowns and expensive major repairs.

1. Engine Oil:

   • Check: Every day before driving, with the engine off and cool, pull the dipstick, wipe it clean, reinsert it fully, and check that the level is between the "Min" and "Max" marks.

   • Change: Change the oil and oil filter according to the manual's specified intervals (e.g., every 50,000 km) or engine hours.

2. Coolant (Antifreeze):

   • Check: Check the level in the overflow/expansion tank when the engine is cool; it should be between the marks. Never open the radiator cap when the engine is hot!

   • Change: Periodically check its freeze protection level and pH. Change it as per the manual (typically every 2-3 years or longer) to prevent corrosion and boiling.

3. Air Filter:

   • Check: Remove the filter element regularly and clean it by blowing compressed air from the inside out (or replace it if necessary). A dirty air filter increases fuel consumption and reduces power.

   • Change: Replacement intervals should be shorter in dusty environments.

4. Fuel Filter / Water Separator:

   • Drain Water: Every day (after or before driving), drain water from the primary fuel filter/water separator (open the drain valve at the bottom until clean diesel flows out).

   • Change: Replace primary and secondary fuel filters at recommended intervals to ensure clean fuel and protect the expensive fuel injectors.

5. Braking System (Air Brakes):

   • Check Air Pressure: After starting the vehicle, observe the air pressure gauge to ensure the system builds pressure correctly (usually to 8-9 Bar or 115-130 psi).

   • Check for Leaks: Listen for obvious air leaks after shutting off the engine.

   • Check Wear: Regularly inspect the condition of brake linings (pads/shoes) and drums/rotors for wear.

6. Tires:

   • Pressure: Check the pressure in all tires (including the spare) daily with a tire gauge. Adjust immediately if not to specification.

   • Visual Inspection: Look for irregular wear, cuts, bulges, and embedded objects.

   • Tread Depth: Ensure tread depth is above legal and safety requirements.

7. Lights & Electrical:

   • Light Check: Have a colleague help you check all exterior lights (headlights, fog lights, turn signals, brake lights, reverse lights) every night or morning.

8. Chassis:

   • Fasteners: Periodically check key components like leaf springs, U-bolts, and driveshaft bolts for tightness.

   • Lubrication (Greasing): Lubricate grease points (zerk fittings) on steering linkage, suspension bushings, etc., at recommended intervals ("greasing" or "chassis lube").

3. Basic Troubleshooting for Common Problems

1. Engine Won't Start:

   • Symptom: Starter motor doesn't crank or is weak.

     • Possible Cause: Weak/dead battery, corroded/loose battery terminals, faulty starter.

   • Symptom: Starter cranks strongly, but engine doesn't fire.

     • Possible Cause: Out of fuel, clogged fuel filter, air in fuel system (requires bleeding), ECU fault.

2. Loss of Power / Excessive Smoke:

   • Black Smoke: Incomplete combustion. Check for clogged air filter, faulty injectors, or turbocharger issues.

   • Blue Smoke: Burning oil. Check piston rings, valve seals, etc.

   • White Smoke: Water in fuel (or, less commonly, a failed head gasket allowing coolant into the combustion chamber).

3. Brake Problems:

   • Soft Brake Pedal / Pulling: Worn linings, faulty brake chamber/slack adjuster, air in the lines (requires bleeding).

   • Slow Air Pressure Build-up: Faulty air compressor, clogged air dryer, or significant air leak in the system.

4. Unusual Noises:

   • High-pitched squeal: Often worn brake linings (indicator screeching) or a slipping belt (fan/alternator).

   • Rhythmic "thumping" noise: Changes with vehicle speed. Could be a tire issue (bulge, separated tread, stone stuck in tread) or a failing wheel bearing.

   • Heavy metallic clunking: Likely from the chassis, e.g., broken leaf spring or loose U-bolt.

4. Recommended Learning Path

1. Start with PMs: First, master basic preventive maintenance: changing oil and filters, greasing, and performing daily checks.

2. Find a Mentor: If possible, learn under the guidance of an experienced technician.

3. Formal Training: Consider attending a vocational technical school or manufacturer-sponsored training courses.

4. Combine Theory and Practice: Consistently study service manuals and technical bulletins, and apply that knowledge practically. Many online platforms (YouTube, specialized forums like TruckersReport, DieselHub) offer extensive repair videos and case studies.