Chances are, the used boat you buy will be sitting on a trailer. Odds also are good that any money the previous owner spent to make the boat more appealing was not spent on the trailer. That means if you want to be sure you get your boat to the water, you should give the trailer a good once-over before heading out.
Good news: trailers aren’t complex, so maintenance — even when deferred by a previous owner — is correspondingly simple. The systems that need regular maintenance are, in order of importance: brakes and bearings, electrical components, couplers, jacks, and bunks. Let’s take them one at a time.
With regular flushing, a year and a half is about the average lifespan for a set of drum brakes used in salt water, so if the previous owner was lackadaisical about flushing, plan on replacing the assemblies. Go for the whole shebang, which includes shoes, backing plates, hardware, and wheel cylinders. It sounds expensive, but it’s not. Figure about $220 for a pair, and they come assembled, so all you have to do is bolt them on.
If you have the brake drums and hubs off, you’ll be into the bearings. These can be the biggest headache of all if you don’t service them, and they are usually the reason you see boat trailers stranded by the roadside.
Most likely you have cone and cup bearings. If that’s the case, be sure you have a set of stainless steel Bearing Buddy caps installed. A Bearing Buddy will keep water out, but it also will tell you immediately when your bearings are low on grease. If the outer spring is compressed, they’re full. If the spring is extended, add grease till the spring compresses fully. Regardless of how often you top them off, pull them apart at least once a year and clean, inspect, and repack them with fresh grease and always, always use new seals.
You won’t need to grease a trailer’s electrical components, but you will need to inspect them to ensure they work properly. First, see if all your lights are working. Then have someone step on the brake pedal and actuate the turn signals to see that they work. As you can see, much of the maintenance involved in electrical systems is a mere matter of inspecting them. Also, be sure to inspect the rubber grommets where wiring enters and exits the frame. If they’ve fallen out or rotted away, your wires can chafe and ground out. If you do have to replace any of the lamps, spring for sealed LEDs, which are more reliable because there are no incandescent bulbs to fail.
For your coupler, jacks, and bunks, it’s also largely a matter of inspection. Check your coupler for proper function. Be sure the coupler latch moves the collar that locks under the hitch ball. Also, look up into the coupler to inspect wear. Though it is rare, hitch balls have actually worn through the top of the coupler, so be sure the coupler stays greased. Do it the easy way, without getting your hands dirty: Two or three times a year, simply turn a tub of grease upside down and lower it onto the trailer ball. Grease will stick to the ball, which will lube the trailer coupler when you hook it up. Shoot some penetrating lubricant, such as WD-40, into the moving parts.
The tongue jack also needs lubrication. Many of them have a grease fitting for the rack and pinion inside. If your jack has a lock pin with a spring-loaded ball, shoot some penetrating lubricant on it, too.
Urban legend has it that some people have lubricated their bunks with Pam cooking spray, and ended up losing their boat off the trailer as they backed down the ramp. We don’t know whether it’s true, but it’s a good idea to leave the winch strap attached to the bow eye until you have the boat in the water. As for lubricating the bunks, it’s largely unnecessary. You do need to be sure the carpeting that covers them is in good shape and that the wood the carpeting is stapled to is sound. Inspect the carpet to see if there are any tears in it that would expose the wooden bunks. If so, replace the carpet. Bunk carpeting can tear a bit more frequently on trailers that carry stepped-bottom boats, because the steps rub the material as the boat slides up and over the forward edges of the bunks.
A lot of maintaining a trailer is paying attention to it on the days you use it. When launching, look at the bunks. When hooking it up, check the coupler, and check the lights each time you go out. Maintaining a trailer isn’t fun, but doing it right means you get to the water every time. And that is fun.