Most boat trailers are relatively simple unpowered vehicles, so the types of repairs that they require are fairly limited. Boat trailer repairs are usually confined to a few basic categories, including the wheels, electrical system, and loading mechanism. Wheel associated issues may include axles, brakes, and tires, and electrical boat trailer repairs can involve the plug socket, wiring harness and lights. The loading mechanism may include a winch and either rollers or slides that the boat rests on, and in some cases there may be hydraulics involved as well.
Boat trailer repairs are typically associated with either wear issues or problems that arise from repeatedly submerging the vehicle. In order to maintain a boat trailer in a good state of repair, a number of items should be regularly checked. One regular maintenance item is tightening the tongue lock, which is the component responsible for fastening the trailer to a hitch. It can also be a good idea to regularly check the wheel bearings and repack them if necessary, since they can be submerged in the normal course of use. Some wheel bearings are sealed, in which case they do not require service unless they fail.
Brakes can fail either due to wear or repeated submerging. Most boat trailers use brake shoes and drums that are activated hydraulically or mechanically. The shoes can become contaminated when submerged, and may eventually crack due to repeatedly getting wet and then drying out. If the brakes are hydraulic, there can also be boat trailer repairs associated with that system. There will typically be a brake master cylinder that can fail along with a slave cylinder inside each drum.
Wiring is another item that can fail prematurely due to being submerged in water. The wiring harness will typically connect to a plug socket at the front end of the trailer and then run back to the lights. Wires will also connect to the brake master cylinder actuator if one is present. Boat trailer repairs associated with this system typically involve inspecting the wires and replacing any that have started to corrode.
The loading mechanism is another system that can require repairs. Most boat trailers either have slides, rollers, or a hydraulic lift. Rollers are typically made of rubber or similar substances and allow the boat to be pulled on by a winch. The winch is another component that can require repair from time to time, and it may be either manually operated or electric. Slide type boat trailers typically must be submerged to some degree so that the boat can float, and hydraulic lifts can be slid under the boat and then activated to raise it up.