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End of Season Trailer Maintenance

Here are a few simple procedures to extend the life of your boat trailer.
Simple end of season TLC will add years to trailer life, save time in the spring and can be completed in an afternoon. Only basic tools are required for most steps, and it does not require a trained mechanic. The focus here is on three main areas:
  • contact points with the boat
  • trailer lighting system
  • over the road components

Rollers and Bunkers

Contact points between boat and trailer become your boat's stability when rolling over land. These contact points, rollers and bunkers, must fit your boat's unique contours. Assessing their health is best done before hauling the boat. That way parts can be replaced without the boat sitting on it. A thorough inspection should look for signs of wear, corrosion and distortion.

Rollers need replacement after so many seasons, sooner if the boat sits on the trailer much of the time. The most common type, black rubber rollers, dry rot from oxidation and repeated submersion in salt and fresh water. Keel rollers in particular are prone to tremendous wear as most weight is centralized there. Inspect for wear and make sure they spin freely. Replace any cracked or distorted rollers with the same type, measured by bracket width. Consider upgrading rubber rollers to Non-marking Vinyl Rollers for a longer life and non-marring on gelcoat. You will need Roller Shafts and Pal Nuts on hand when replacing rollers.

Bunk trailers use either bunk rollers and or carpet-covered bunk boards to cradle and support the hull curvature. Bunks are typically located just below the chine on most planing powerboats. Inspect rollers to make sure they spin freely. If the trailer instead has boards, inspect and replace areas where the bunk carpet may be torn and exposed. Marine carpet helps shed moisture away from the hull and prevents gouging. Carpeting also lessens friction to ease the boat on and off the trailer. If your carpeted bunk trailer requires extreme force to launch or haul, (usually the case at shallow angle ramps), consider improving the bunk with Bunk Slicks. Slicks help the boat glide over the bunks when wet and is safer than soap.

Once the boat is loaded and clear of ramp traffic, check the balance and fit before hitting the road. The keel centerline should be aligned to the center of keel rollers as closely as possible. Misaligned boats cause fishtailing when towing, an experience you won't want to repeat. Be sure the boat is centered and the weight distributed evenly right to left. Guide posts make driving the boat onto the trailer center a cinch and a repeatable performance with minimal effort. Next, make sure both bunks contact the boat. If not, the boat will wobble side to side on the keel rollers. Most bunk supports are adjustable in height to correct this problem. With the side to side in center, we next need to check the boat is balanced front to back. The bow stop is your reference point. With the boat winched snug to the bow stop notch it should be in balance fore and aft over the axle. A balanced trailer should have about 10 lbs of downward force on the tongue when the trailer is level. This can be measured with a simple bathroom scale propped up on some blocks so it meets the tongue at a level position. You should be able to lift the tongue easily in one hand when balanced. If tongue weight is too much or little, bumps in the road become exaggerated as the trailer tongue torques the rear suspension of the tow vehicle. To fine tune the balance, either the axle location needs adjustment along the trailer frame (loosen connecting points with boat off trailer and slide to ); or boat placement on the trailer needs to move forward or back to achieve the desired balance. The location of bracket arm holding the winch and bow stop can typically be adjusted on most trailers. Simply back off the securing U-bolts, shimmy the unit forward or back, and torque the bolts back in place. At this point the rollers should all contact and support the boat hull. The result- a balanced ride that tows predictably and does not bounce the suspension of the towing vehicle with every bump. Finally, before heading out, lock the transom down with tie-down straps so your boat stays put.

Trailer Lights

Next on the list are trailer lights- you know- the ones perennially crunched off when backing the trailer in a tight spot.

  1. First step is to make sure all lights are functioning and none of the housings are cracked. Winter is a great time to replace any "working on it's last limb" bundles of cracked plastic and tape for a properly sealed housing. Typically, incandescent style festoon or bayonet bulbs sit in plastic housings that are open on the bottom to drain out water. They work on a bell jar principle where air compresses, but since housing is sealed on top, water never completely reaches bulb in normal operation. If housing is cracked the bulb contacts will get dunked and corrode. Newer LED style lights come as a sealed unit and are replaced wholesale. If you have traditional bulb flavor, open the housing and temporarily remove the bulb. Wire brush contact points to shiny metal, grease and replace. Do this to each light. Since LEDs are sealed unit, there is no maintenance- replace LED's when they stop working.

  2. Inspect the pigtail connection between vehicle and trailer. Again, wire brush any visible corrosion to shiny metal. For female connection points, a scrap of wet/dry sand paper rolled between fingers works great. Spray with WD-40 or similar corrosion inhibitor and penetrating lubricant.

  3. Next, trace wiring from the pigtail connector along the frame and inspect for exposed wire and chafe points. Any exposed wire and electrical connections are time bombs for corrosion. If your lights are dim, working on their own schedule or not at all, replacing the entire system is easiest. A trailer light kit is the most cost and time effective solution since water intrusion wicks up a wire inside the insulation and causes corrosion far beyond the point of entry. For most folks, the dollar difference for a new lighting kit is worth the time savings of inevitably chasing down corrosion. Hang onto the old intact housings for emergency spares.

Light kits are available in either standard or LED type. LED's draw significantly less battery power and have a much longer life expectancy. Trailers over 80 inches wide require amber side clearance lights, thus kits are specified for either under 80 light kits and Over 80 Light Kits. Kits should include wiring harness, connector, license plate holder and all parts needed. Look here for a How-To on light replacement. Trailer Wire Connection Testers are the easiest way to make sure your pigtail harness from the vehicle is supplying clean power. This should be the first step in troubleshooting to save aggravation. Last word on lighting, use dielectric grease. This grease insulates electrical connections to improve reliability and chase out corrosion. Pure silicon grease also works for this purpose.

Tires, Wheels, Hubs and Brakes

The last step but arguably most important is the ride of the trailer. Start with a simple tire pressure check. The recommended pressure should be marked on the sidewall of the tire. If the tire is so old you cannot read the markings, and the cracking in the sidewall is big enough to hold loose change, no amount of tire magic is going to fix that baby. If your trip is longer than the length of your driveway, it means you are traveling over public roads and are liable for accidents caused by a blowout. Be leery of running bad tires over the road. A pair of Rim Mounted Trailer Tires is half the price of automobile tires and lasts the average boater a good long time. To extend the life, try spraying some 303 Protectant on cleaned sidewalls before stowing the trailer for winter. For extended layup intervals block the trailer from the frame. Not only will this prevent dry rot, cracks, distortion to tires, it also greatly reduces chance of theft. Next bring your attention from the tires and rims to the wheel itself. Give a quick spray of penetrating oil on the lugs to minimize corrosion. Most importantly, inspect the hubs. These lubricated connections keep the wheels from burning up and destroying the axle. Grease if necessary, usually annually depending on mileage. There are several types of hub fittings in use today, but most common is the simple greased hub. Apply trailer bearing grease with a grease gun through the zirc fitting. The instructions for the Tie Down Wheel Hub Kit offer more info on proper lubrication. If the hubs are worse for wear, consider upgrading to the increasingly popular Bearing Buddy system. Bearing Buddy completely seals the hub from water intrusion with spring loaded positive pressure. The design compensates between increased heat at high speeds to the cold shock of dropping the hub in water. If your trailer incorporates brakes, trace brake lines along the frame to carefully inspect for leaks and double check the brake fluid level usually located on the trailer tongue. A Drum Brake flush kit is easy to install and can help you quickly flush out corrosive road debris and saltwater from any drum brakes by simply attaching to a garden hose. Be sure to inspect the brake actuator on the tongue as well and give an over-all coating with WD40 . Completing these steps means you will be ready to roll and beat the crowds next spring!

Secure the Boat

Before you walk away, be sure to eyeball the level of the trailer and incline the bow so all water easily drains out the transom. Block the trailer under the tongue and transom to prevent the see-saw danger, or better yet, block the trailer with tires off the ground as previously mentioned. Make sure all plugs are removed. As good habit, place these plugs in a ziplock bag and ziptie them to the steering wheel to eliminate the chance of losing or forgetting to replace them come spring. You are now ready to relax and rest up for the next phase of engine and boat winterizing. Nice work.

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