Maintaining a trailer is simple, but if you don't take care of the little things, you could be in for a big letdown.
Your trailer should give you years of service, but you do have to perform periodic maintenance to keep it working properly.
A freshwater rinse after every dunking will keep critical trailer components like brakes and springs from rusting away prematurely. A quarterly spray with corrosion inhibitor on your springs, brakes, wheel lugs and other steel parts will prevent corrosion.
Boat trailers live in two notoriously hostile environments: on the highway and in the water. That means regular maintenance — especially of bearings, brakes, and wiring — is crucial to keep them safe and legal. Tires are a critical component, too, and should be stamped with an "ST" classification, for "special trailer." Dedicated trailer tires are more durable and resist abrasion and impact better than passenger "P" tires or light-truck "LT" tires; they also bounce less. Make sure the tire is neither over inflated nor under-inflated, and that the weight on the trailer doesn't exceed its capacity. Divide the trailer's total gross weight (measure it at a public weigh station) by the number of tires. Towing your trailer with the frame level and parallel to the road is important especially with tandem or triple torsion axles.
Maintaining Trailer Brakes
Disc brakes offer more stopping power. Most states require brakes to be fitted on trailers with a gross weight over 3,000 pounds. Many experts recommend them on trailers rated for 1,500 pounds and above. Trailer brakes can be mechanical, electrical, or hydraulic. Hydraulic "surge brakes" are the most popular technology. The entire system is contained in the trailer itself; any number of different vehicles can tow it. Like other hydraulic systems, this one is based on the fact that liquids cannot be compressed. A master cylinder is located inside the trailer's coupler device. When the towing vehicle brakes, inertia from the decelerating trailer drives a piston inside the master cylinder, increasing the pressure of the hydraulic fluid all through the brake lines. Be sure you have a 5 wire trailer connector on your vehicle. The 5th blue wire controls the trailer brake lock out solenoid which allows you to back the trailer up a grade.
There's a lot going on in your trailer's coupler device including a master cylinder for your brakes. At the other end of the brake lines, this pressurized fluid drives the braking device — either calipers in the case of disc brakes or a brake cylinder in the case of drum brakes. Disc brakes consist of a rotor oriented in the axis of the wheel. During braking, a piston drives calipers that squeeze against the rotor, creating friction to stop the wheel. By contrast, drum brakes consist of a wide cylinder section. During braking, a curved shoe inside the drum presses against the drum, slowing the wheel.
Drum brakes work better in wet conditions and are self-adjusting. Disc brakes tend to have greater stopping power and greater fade resistance than drum brakes, and function better in wet conditions. They're also self-adjusting and easier to inspect and maintain. That said, their rotors are typically made of steel, which is prone to corrosion. Rinse metal parts thoroughly with fresh water after every launching.
Brake pads are a routine-wear item. Follow manufacturer's instructions for indications of when it's time for replacement. Brake lines are another regular-service item. Fluid levels should match the manufacturer's recommendation. If they call for, say, new "DOT 3 brake fluid," don't substitute anything else; seals and other components depend on the right blend. If brake lines need to be either replaced or bled, carefully follow manufacturer's instructions.
Winch straps or cable must be inspected and replaced if showing signs of fraying, chaffing or fading. If you feel you might snap a cable or strap when cranking the boat on the trailer you might have the trailer adjusted improperly or the trailer is not far enough in the water. See your dealer for assistance with this.
Coat all steel or iron parts with a good quality corrosion inhibitor. Lug nuts, brake parts (not where pads contact rotor or drum). Lubricate tongue jack, winch and coupler mechanisms with a spray lube like WD-40.
Always check your lights for proper operation before each trip. A good tip is to buy a test plug that inserts in your vehicle’s trailer plug connector. This tests the vehicle and allows you to easily isolate a problem. They are about $6.00 and well worth it.
Be sure to secure your boat from moving forward and back on the trailer. You can use dock lines or ratchet straps to do this quickly and easily. CHECK LUG TIGHTNESS BEFORE EACH TRIP. Verify coupler is secure on the ball and there is a safety pin installed to keep the coupler from opening on its own. Cross safety chains and make sure they are securely on the vehicle hitch point. Always check tires for correct pressure, overheating or uneven wear at any gas stop.