How to Maintain Your Boat Trailer
Towing a classy boat makes you feel like the King (or Queen) of the Road. Keep it that way by maintaining your trailer like a pro.
Boat Ramp Champ
Towing a classy boat makes you feel like the King (or Queen) of the Road. Keep it that way by maintaining your trailer like the pros do.
You just bought a shiny new boat and trailer combo, and a four-wheel-drive pickup that can tow a battleship. You know how to maintain the boat, and the dealer will take care of the truck, but how do you make sure your expensive trailer stays fit and capable of taking you on the adventures you crave? There’s more to trailer maintenance than you might think, and it starts on the first day you own your new rig.
You’ve probably heard this before, but you’ll hear it again now: Read the owner’s manual! The folks who built your trailer didn’t write those instructions for their own amusement—everything you need to know (well, almost everything) is in there, so get familiar with it. If you don’t have a manual, chances are you can download one. Making a trailer last forever isn’t rocket science and doesn’t demand esoteric skills or necromancer’s tools—it’s really just a matter of knowing what simple upkeep chores to do, and when to do them. The first and most important chore in preventive maintenance involves prodigious volumes of H2O—fresh H2O, that is.
If you boat in salt water, your trailer will start to rust the first time you drive home from the ramp. Whether its frame is painted steel or galvanized or aluminum, or whether the frame is box beam or I-beam or C-beam, there are components that will rust. So always, ASAP after reloading the boat, hose the crap out of every square inch of the trailer. If your launch ramp has fresh water, do it there. Otherwise, flush the trailer as soon as you get home. A biodegradable salt remover (I like Salt-Away) mixed with the rinse will do a more thorough job than water alone, as will soap and a brush. Hit the vulnerable areas with corrosion inhibitor frequently; lug nuts and leaf springs just love to oxidize, for example.
Do whatever works to nip rust in the bud. Some folks smear grease on rust-prone components. If the trailer’s painted, touch-up any nicks as soon as possible, like you would your new truck. Treat rust spots with Rust-Oleum or another corrosion-inhibiting paint. Follow the directions for application. A little effort when the trailer’s young will prevent major problems as the years add up.
Baby Needs Shoes
BoatUS says that 44 percent of the calls to their Trailer Assist department involve tire problems. Maintaining tires is about as easy a chore as there is. Keep them clean, treat them with a UV inhibitor and check the air pressure before every trip. Check your tow vehicle’s tires at the same time, and remember the spares. Most trailer pros pump the tires up to the maximum cold pressure listed on the sidewall, but check your trailer manual, too. Over- or under-pressure will show distinctive wear patterns over time.
Don’t rely on visual inspection, especially with a multi-axle trailer. One tire can be soft, or even flat, but you won’t notice because the others take the weight. (That’s why semi drivers whack their tires with a billy club.) Invest in a digital tire-pressure gauge and air pump so you can top off the tires when necessary. I carry a Viair pump that clips to my SUV’s battery, with a hose extension so I can reach the tires on the far side of the trailer without shifting the truck. I also carry a tire-repair kit, so I can pull a nail and plug the hole by the side of the road, and a hydraulic bottle jack powerful enough to lift both the boat and trailer. Check your manual to find where to place the jack under the trailer and measure the clearance there before buying a jack; allow for the tire being flat, and add an inch for the piece of plywood you’ll place under the jack if the ground is soft. Practice jacking up the trailer at home when things are calm. You’ll need the jack for other maintenance chores, too.
Replace tires that are more than, say, seven years old, even if they’re not worn. (Some experts say five years, some say 10; pick your poison.) Rubber doesn’t last forever, and storage outside, often in strong UV light and/or under less-than-ideal conditions, ages them beyond their appearance. Don’t risk wrecking your boat and trailer for a few hundred bucks worth of new booties twice a decade.
Bear With Me
If the tires don’t get you, maybe the wheel bearings will. There are two in each wheel—inner and outer—and they should be cleaned and repacked with marine wheel-bearing grease yearly. Not all wheel-bearing grease is water-resistant, so buy the marine stuff, even though it costs more. Jack up the trailer (before working around or under the trailer, block it with mechanics’ jack stands, heavy timbers, or whatever works; don’t rely on the jack alone) and check the bearings by spinning the wheels and listening for unpleasant noises. The wheels should spin silently. Wiggle each tire top to bottom and side to side; any movement suggests the bearings need closer inspection. Worn bearings complicate things, and rather than DIY it, I’d hire a mechanic to check and replace them if necessary. They have the tools and the expertise.
Let’s say you’ve lived right and your bearings are all okay. There are dozens of videos on YouTube showing how to repack them, but most illustrate the process on a simple hub, with no brake. Drum brakes are easy—the drum is integral to the hub, and comes off with it. Disc brakes complicate the process slightly—you have to remove the caliper assembly before the hub and rotor can be pulled off. It’s only a couple of bolts, but it’s an extra step. On the upside, disassembly forces you to inspect the brakes. Drum brakes on a trailer that’s been used in salt water are likely showing some internal rust, so this is a good time to clean them. Don’t get anything slippery on the brake shoes or the inside of the drum.
Many videos also forget to mention replacing the inner bearing’s grease seal with a new one. Don’t reuse the old seal, which you probably damaged when removing it. It’s a cheap part but does an important job: keeping the grease in the hub and the water out. Bearings will last a long, long time if kept greased, but drenching them in salt water cuts their life expectancy remarkably, and you can rinse with fresh water from now until Doomsday and not flush salt out of the hub. Grease is your best defense here, so don’t slack off on lubing the hubs and bearings. Keep water out of the bearings and you’ll get many years of happy rolling.
Keep On Stopping
Most modern trailers have hydraulic surge brakes, activated by pressure on the trailer tongue. When the tow vehicle slows, the trailer pushes against the hitch, which applies pressure to a master brake cylinder mounted in a surge actuator in the tongue. This, in turn, pressurizes the hydraulic lines and applies the brakes. It’s analogous to stamping on the brake pedal. (Some trailers use electric-over-hydraulic brakes hooked into the tow vehicle’s brake system. They provide greater braking pressure, but the on-trailer components have to be protected from water.)
Checking the brake fluid is easy—the fill is right there on the tongue. Fluid loss will warn you when something’s amiss. Test the brakes for proper function by manually activating the surge actuator using a pry bar or ratchet strap to push against it; use your ingenuity. Block the trailer so it doesn’t roll. The actuator should move into the trailer frame, but not bottom out—hydraulic pressure should stop it. (On most actuators, you can see the movement on the side of the tongue.) If it goes all the way, chances are there’s air in the brake lines, or a line is leaking. Sometimes it’s simply from lack of periodic topping-up. In either case, the brake lines will need bleeding after repair and/or refilling, a real pain without the proper tools. This is another job for a qualified mechanic.
Backing the trailer applies the same pressure to the surge actuator as braking. There’s a solenoid that keeps disc brakes from engaging; it’s tied into the tow vehicle’s back-up lights and plugs in with the trailer’s wiring harness. (Some trailers with drum brakes use a different system, or the drums are designed simply not to engage in reverse.) Make sure the system works before you try to back down the launch ramp and find your wheels just won’t turn. There are mechanical lock-out keys that physically jam the surge actuator; you have to manually insert them. Might be a good idea to carry one in case the auto system craps out.
Take care of the breakaway cable protruding from the surge actuator. It’s basically just a wire with a carabiner on the end, but it’s critical—when connected to the tow vehicle, it actuates the brakes should the trailer come adrift. Before it snaps, the breakaway cable compresses the piston that sets the brakes, like the surge actuator does when the tow vehicle slows normally. Only difference is, the brakes lock, and remain locked even after the crash is over. Careless trailer handling can damage the cable. Replacement isn’t difficult, but you often have to disassemble the surge actuator. (Good opportunity to clean and inspect it.) If you accidentally pull the breakaway cable and lock the brakes, there’s a means to release them, usually a lever on the underside of the actuator. Don’t use the breakaway cable as an emergency brake for parking the trailer—leaving the brakes locked will damage them.
Keep It Clean
Give the tongue jack some attention, too. It will get filthy with road dirt, moisture and salt, and will soon start to corrode. Leave it alone, and one day you’ll want to jack the tongue and it just won’t happen. Rinse, clean and lube the jack per the owner’s manual. When the jack freezes up, disassemble it and give it a thorough overhaul. It’s easy, and, again, YouTube is your friend—there are a bunch of videos that show you how. If the jack has a caster wheel, grease the axle so the wheel both turns and rotates freely. Clean and lube the coupler and the trailer ball, too, and inspect the safety chains.
Keep the winch clean and lubed. Inspect the full length of the strap and replace it sooner rather than later. Spray a wire cable with lubricant to reduce friction and displace water. Unroll a strap all the way and let it dry—do this after every use, since water trapped on the winch drum promotes corrosion. Both the winch and trailer jack can be replaced at not much cost if they’re too far gone.
Finally, buy a good grease gun, keep it filled with the same marine grease you used to pack the bearings, and learn to spot a zerk fitting from 100 feet away. Carry a can of water dispersing spray lube, too; WD-40 or Boeshield T-9 works fine. Don’t be afraid to use it. It’s easier to prevent rust than cure it. Trailers aren’t very sophisticated machines—basically, they just have to roll. It doesn’t take much to keep them working smoothly, and lubricant is the elixir that does the trick. (But remember—be careful not to overfill Bearing Buddies, or you’ll push out the rear seal you replaced when repacking the bearings.)
Give your trailer a minimum of TLC, and it’ll carry your boat comfortably and safely for years. Who knows what adventures you’ll have?
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This article originally appeared in the April 2022 issue of Power & Motoryacht magazine.
Source: https://www.powerandmotoryacht.com/maintenance/how-to-maintain-your-boat-trailer
