The annoying squeak every time a boat trailer rides over a bump in the road can just about drive a motorist crazy. Luckily, by following a simple maintenance procedure, you can eliminate that squeak. The critical leaf spring of the trailer connects to the axle and the chassis of the trailer, suspending the wheels and absorbing shocks. The shock absorption is why it squeaks so often. As you lubricate this spring, you'll also protect it against unnecessary wear and tear.
Raise the trailer up off the ground, or slide underneath it to observe the undercarriage of the trailer.
Find the leaf spring, which is usually comprised of several long, skinny, flat "leaves" of tough carbon steel. The leaf spring holds up the axle, either by running parallel to it and holding it up from above, or by using two springs running perpendicular to the axle, one near each wheel.
Spray lubricant along the spring, paying close attention to areas where metal parts rub against one another.
For example, make sure the connections and bolts between the axle, wheels and spring receive ample lubrication.
Lower the trailer back onto the ground, or slide out from underneath it.
Test the squeak by applying a load onto the trailer.
Repeat as necessary.
