Common Trailer Parts Failures and Solutions

1. Braking System Failures (Core Safety System)

• 1.1 Failure: Abnormal Brake Pad/Lining Wear, Overheating, Noise

• Regular Inspection & Replacement: Replace pads/linings before wear limits; always replace in axle sets.

• Check Brake Actuators: Ensure proper piston retraction; lubricate slides/camshafts.

• Inspect Wheel End System: Verify proper bearing adjustment; check for looseness or damage.

• Normal wear limit reached.

• Brake caliper/slack adjuster sticking (causing drag).

• Wheel hub bearing failure (leading to disc/drum runout).

• Clogged air lines or air pressure imbalance.

  
  

• 1.2 Failure: Brake Failure or Weak Braking Force

• Pre-trip Air Pressure Check: Monitor gauge for proper pressure build-up rate and value.

• Listen for Leaks: With engine off, hold brake pedal to check for audible air leaks.

• Replace Air Dryer Regularly: Annually or as per mileage to ensure dry air.

• Professional Valve Diagnosis: Mechanics should test valve output pressures.

• Low Air Pressure: Air compressor failure, clogged air dryer, faulty multi-circuit protection valve, air leaks.

• Brake Fluid Leak (Hydraulic systems): Leaks from master cylinder, wheel cylinders, or lines.

• Valve Malfunction: Faulty foot brake valve, relay valve, or ABS modulator.

  
  

• 1.3 Failure: ABS Warning Light Stays On

• Causes: Dirty/damaged wheel speed sensors, damaged tone rings, wiring faults, ECU failure.

• Solutions: Clean sensor heads, check sensor-to-ring gap, read fault codes with diagnostic tool.

2. Suspension System Failures (Affects Ride & Cargo Safety)

• 2.1 Failure: Trailer Pulls to One Side or Severe Tire Scrubbing

• Adjust or replace height valve linkage.

• Inspect leaf springs; replace broken leaves or worn bushings.

• Perform Trailer Alignment Regularly: After set mileage or upon noticing uneven tire wear.

• Faulty/disconnected height control valve (air suspensions) causing uneven ride height.

• Broken/shifted leaf springs or worn bushings (mechanical suspensions).

• Misalignment: Axle tracking or toe-in settings out of specification.

  
  

• 2.2 Failure: Suspension Noises (Clunking, Metal-on-Metal)

• Causes: Severely worn spring hanger pins/bushings; loose U-bolts; worn equalizer beam bushings.

• Solutions: Tighten all fasteners; replace worn pins and bushings.

3. Electrical & Lighting System Failures (Safety & Compliance)

• 3.1 Failure: Tail, Turn, or Stop Lights Inoperative/Intermittent

• Use Dielectric Grease: Apply to all electrical connectors to prevent moisture/corrosion.

• Inspect & Repair Harness: Protect vulnerable wiring with loom or tape.

• Clean Ground Points: Ensure frame ground connections are clean, tight, and bare metal.

• Upgrade to maintenance-free LED lights for longer life and vibration resistance.

• Wiring Issues: Corroded/loose connectors (especially 7-pin plug); chafed wires shorting.

• Poor Grounding: Corroded ground connection points on trailer frame.

• Bulb Failure.

  
  

4. Tire & Wheel End System Failures

• 4.1 Failure: Abnormal Tire Wear (Shoulder wear, Cupping/Scalloping)

• Causes: Axle misalignment, loose wheel bearings, out-of-balance wheels.

• Solutions: Perform trailer alignment; adjust wheel bearing preload; balance tires.

• 4.2 Failure: Excessive Hub Heat ("Burned Bearings")

• Regular Wheel End Service: Lubricate with correct grease at recommended intervals.

• Use High-Quality Seals: Install reputable brand seals during service.

• Use Infrared Thermometer: Check hub temperatures during stops for early detection.

• Causes: Lack of lubrication/bearing damage, failed seal causing grease loss, excessive bearing preload.

• Solutions:

•  Regular Wheel End Service: Lubricate with correct grease at recommended intervals.

•  Use High-Quality Seals: Install reputable brand seals during service.

•  Use Infrared Thermometer: Check hub temperatures during stops for early detection.