What are common signs of water intrusion and hub contamination?

Boat trailers, especially those with submersible wheel hubs, are prone to water intrusion and hub contamination if not properly sealed and maintained. Recognizing the early signs can save you from costly bearing failure or wheel lock-ups on the road.

Here are the most common signs of water intrusion and hub contamination in boat trailers:

1. Grease Discoloration

• Normal grease is usually blue, red, or green (depending on the type).
• If water has intruded, the grease often turns a milky, gray, or chocolate color due to emulsification.

2. Excess Grease Leakage

• If you see grease being forced out around the dust cap or seals, it may indicate:
  • Water is displacing the grease.
  • Pressure build-up due to poor venting or over-pumping.

3. Visible Rust or Corrosion

• Water intrusion leads to pitting or rust on the spindle, bearings, or races.
• You may also notice orange streaks around the hub area.

4. Bearing Noise

• Contaminated hubs often produce:
  • Grinding, humming, or growling sounds when towing.
  • A metal-on-metal squeal if the bearings are severely worn.

5. Excessive Heat

• After towing, touch the hub cautiously (without burning yourself).
  • A normal hub should feel warm but not hot.
    • Overheating hubs suggest contaminated or failing bearings.

6. Grease Leakage on Rims or Tires

• Water can push grease out past the rear seal or cap, leaving streaks on the wheel or tire.

7. Loose or Wobbly Hubs

• Lift the trailer tire slightly off the ground and wiggle it side to side. Any play or looseness may indicate worn bearings due to water contamination.

8. Cloudy Hub Covers (Oil Bath Systems)

• If your trailer uses oil bath hubs, cloudy or milky oil is a direct sign of water intrusion.

✅ Preventive Tip:
Always check your bearing protectors, seals, and dust caps before launching. Grease should look clean and fresh, and seals should be snug. Re-grease hubs with marine-grade grease every 3 months or 1,000 miles to prevent water damage.