Boat trailer bearings are often under looked or forgotten. The thing is that, if not maintained regularly and properly, a faulty or seized bearing can ruin your weekend. I had this happen to me and would want you to learn from my mistake. Here I have compiled all the information you’ll need to take good care of your boat trailer bearings.
So how often to grease boat trailer bearings? Every 3,000 to 3500 miles or annually, whichever comes first. Manufacturers recommend to remove old contaminated grease from the hub and repack with new grease instead of just adding more.
Unlike regular trailers, boat trailers get submerged in water on regular bases. This is why these types of trailers require service and inspection more often. Remember that sitting on top of that old trailer is your precious boat, taking good care of the trailer will ensure that you can tow your boat to and from the water without any incidents.
How To Repack (Re-grease) Boat Trailer Bearing
Repacking your boat trailer bearings is the best way you keep your trailer rolling smooth. It will take you about one hour, but it will save you a lot more in the long run.
Stuff you’ll need
- Mallet
- Flathead screwdriver
- Rags
- Grease
- Liquid sealant
- Jack
- Jack stand
- Adjustable wrench
- plyers
- Bearing Packer
How to pack bearings
- Place wheel chocks on the side you are not working
- Before jacking up the trailer, loosen up lug nuts; this way, the weight of the boat and trailer will prevent the tire from spinning.
- Jack the trailer up enough so that the tire you are working on can spin freely and place jack stand to support the trailer.
- Remove the bearing buddy or dust cover. You can use a flat head screwdriver to pry it out or a mullet to tap it from side to side until it brakes loose.
- Wipe grease with a rag and remove the cotter pin, axle nut and spindle washer.
- Remove outer bearing. if it gets stuck, shake the tire from side to side, and it should come right off.
- Pull off the hub from the spindle and repeat the proses to remove the inner bearing. You might have to use pliers or a seal puller to remove the seal.
- Use a rag to clean relly god al the components
- Use a packer (link to amazon) to pack new grease into the bearings. If you don’t have a packer, place some grease on the palm of your hand and use your fingers to push it into the rollers until it comes out the other side of the bearing.
- Place a film of fresh grease on the bearing races and put everything back the way it was. Don’t forget to Coat the outer edge of the seal with liquid sealant.
- Install dust cover or bearing buddy, and you are done.
When in the proses of packing your boat trailer bearings also keep an eye for anything that might not look write like:
- Cracks
- Rust
- Decoloration
- Lose metal particles
- Pitting
- Dents
If you find any of these signs of deterioration, it is better to replace the bearings instead of packing them. New bearings are inexpensive and can save you a headache later. So if anything looks shady or doesn’t feel right, just go ahead and replace them.
When cleaning the old grease off the bearings, it is best to use paper towels or rags. The use of strong chemicals like gasoline can damage the inner seal.
Can You Over Grease Trailer Bearings?
If not using a bearing body it is indeed possible to over grease your trailer bearings and blows out a seal. Also according to the experts at Machinery Lubrication:
Too much grease volume (overgreasing) in a bearing cavity will cause the rotating bearing elements to begin churning the grease, pushing it out of the way, resulting in energy loss and rising temperatures. This leads to rapid oxidation (chemical degradation) of the grease as well as an accelerated rate of oil bleed, which is a separation of the oil from the thickener.
The heat that has been generated over time along with the oil bleed eventually will cook the grease thickener into a hard, crusty build-up that can impair proper lubrication and even block new grease from reaching the core of the bearing. This can result in accelerated wear of the rolling elements and then component failure.
Machinery Lubrication
How Long Do Boat Trailer Bearings Last
It is hard to say a specific number when talking about boat trailer bearings. Some experts give them a life span of 85,000 to 100,000 miles. But the real answer is that it depends on many factors. Trailer bearings that are properly maintained can out-last the trailer itself.
Unlike regular trailers, The #1 issue with boat trailers is that the bearings get immersed in water and can, therefore, easily become contaminated and begin corroding because of the water intrusion without this fact being readily noticeable.
Also, when you drop your trailer on the water and the bearings are still hot, the contact with cool water will create a vacuum effect on the hub. When this happens, water can still get in the hub even with good seals
Bearing buddies have a spring-loaded piston that pushes against the grease and releases the pressure so that the vacuum effect shouldn’t happen.
How To Prevent Water From Getting To The Bearings
The best way to keep water out of the bearings is preventive maintenance and routine inspections of the hub and dust cover. When doing your inspection, look for damage or missing dust covers and replace immediately to prevent water or dirt from getting in. Also, look for any signs of a broken seal, for example, grease all over the wheel. A broken seal will also allow the unwanted water in, replace immediately.
Another thing to do is to try not to submerge your hot bearings in water. You might have the temptation after a long trip on the highway to go straight to the ramp to drop the boat. It is best if you wait a few minutes and give the bearings a chance to cool off, this way you’ll avoid creating that vacuum effect on the hub.
What Are Bearing Buddies
The bearing buddies are created to protect and prolong the life span of the bearings by keeping dirt and water out of the hub. The fill-up valve on the bearing buddy will also prevent overfilling and rear seal damage with an automatic pressure relief feature.
The axle hub is filled with grease until the grease forces the Bearing Buddy® piston outward about 1/8 inch. Because the piston is spring-loaded, the piston exerts a slight (3 PSI) pressure against the grease, which maintains a slight pressure between the inside of the hub and the outside environment. When the hub is submerged, water cannot enter the hub because of this pressure. An automatic pressure relief feature prevents over-filling and over-pressurization. See Bearing Buddy diagram: Without this feature, the inner seal will be damaged.
Trailering, even a short distance, heats the hubs. When the wheels are submerged during launching, the hubs suddenly cool and the air inside the unprotected hubs contracts, forming a vacuum that draws in water through the rear seals. There is no such thing as a rotating seal that stays perfect. Water and grit, thus drawn into the hubs relentlessly destroy bearings. When properly installed and maintained, Bearing Buddy® prevents wheel bearing failure and eliminates bearing repacking. Boat trailer wheels can be completely submerged.
Bearing Buddy
Do You Need Bearing Buddies?
You certainly don’t need bearing buddies on your boat trailer. That been said, installing the buddies on your boat trailer will definitely help prolong the life span of the bearings. The maintenance cost and time will also be reduced. So it is one of those things that will make your life easier. Here is a link to the bearing buddy on amazon.
Here are links to the stuff I use when servicing my trailer
- Lucas Oil 10320 Marine Grease; Multi-Purpose;14 Ounce (link to amazon)
- REXBETI Grease Gun, Premium Pistol Grip Car Grease Gun Set with Flex Hose, 2 Reinforced Coupler Included (link to amazon)
- GEARWRENCH Hand Bearing Packer – 2775D (link to amazon)
