What;s the deal on trailer bearings?

[Lootas1]

I've had trailered boats for many years and only replaced wheel bearings one time. Someone told me that the Bearing Buddies only keep grease on the outside bearing and the inner bearing still gets soaked (in my case, saltwater about once a week in the summer). Is this true? Do I need to pull the wheels and repack the bearings with some frequency. What are the rest of you doing? Most of my use is from house to boat launch at most 1/4 mile away but don't want to take the trailer out on the highway and have a bearing or two go to pieces.

[Tim McCrain]

oh boy ...

Jerry,

If you search the boating forums you'll find never ending discussions / arguments on this subject, which never fails to bring out widely varying opinions, many filled with outrageous claims on both sides.

The idea behind bearing buddys or other brands is that if the hub is filled with grease and under positive pressure, it prevents the entry of water into the hub, both by pressurizing the seal and by simply not allowing any room for the water inside the hub. Many people swear by them.

What they absolutely do not do, despite claims to the contrary, is pack your wheel bearings for you, or cause them to be constantly packed as you drive by forcing grease into them under pressure. I've also read opinions that when the entire hub is packed with grease, it will migrate into the bearings when everything gets good and hot. Neither of these hold water. (pun intended)

If the hub is pressurized, it is pressurized equally throughout the hub, which will not force grease from the center of the hub into the bearings. If grease would flow from the center of the hub into the bearings when everything got hot, then the grease would be of such poor quality that it wouldn't protect the bearings. Grease will certainly become less viscous when heated, and migrate through a bad seal onto the inside of your wheel, but to think it will magically flow from the center of the hub into the bearings and then stay there on its own is wishful thinking.

As a former mechanic, I tore down a lot of hubs with ruined bearings with hubs packed full of grease. The bearings only have so much room for grease, as long as the bearings themselves begin their service packed full, it doesn't matter how much grease sits in the hub next to them, or how much pressure you apply to the hub. The little teeny tiny layer of grease on the rollers is all that matters to the bearings. The biggest factors affecting trailer bearings, beside water intrusion, is high speed use with small wheels and improper adjustment.

In my opinion, there is no substitute for tearing down your hubs at the end of every season, cleaning and packing your bearings, inspecting the spindle for wear and installing new seals. Unless, of course, you install double-sealed oil bath hubs, which are pretty cool. (another pun ...)

Tim

[Lootas1]

Let's hear more about double sealed oil bath hubs. The only time I replaced bearings, it was a very messy job and costly and I'd prefer never to have to touch a trailer wheel bearing (yet not quite enough to haul the trailer to town and pay $50 ferry fare and price of repacking (or replacing) bearings. Besides I'm somewhat lacking in inspecting skills. Guess I'd be able to see a spindle that was totally rusted or worn down to pencil size. Must be a fortune in it for the person who invents the lifetime trailer bearing!

[Helmar]

For the non mechanic, the best thing is to keep jacking in the Marine grease.
Keep pumping it in and it will seep out the rear oil seal.

It will only hold so much until it blows the seal our of the rear (pumping in too much pressure) and then most of the better hubs have a spring in the front where you can see it move once the hub is packed and no more room for grease.
Once it moves out as in Full, then stop.
Just keep the grease gun handy and when you see the spring release or more room for grease to be added, then its simple, Add more grease.

Like I said, its better than doing nothing until along side the road with a spindle burnt to the point you need to replace the whole axle.....:Runaway1:

[Skagitguy]

Jerry, I just take it to LS Tires Center. Screw it. Let them do it and that way they have to back up there service agreement . There is a grease fitting on the back of the King trailer on the inside of the axle. Hard to see. Chuck

[Lootas1]

Thanks Chuck. I'll get out there and find it and shoot some grease in. Never knew of grease fittings on the inside. Think you are right, some day when I plan to take Rosario down the road, I'll take her to a shop and have the bears checked and repacked the day before we are going somewhere and drop the trailer at one of my son's place on the mainland to pic up the next day.

[westerner]

Jerry, just as a quick check on my bearings, I keep a SUV car jack in my carport and before I take any trips of any distance I just jack up the trailer and spin the wheel. (The trailer should be hooked up to the tow vehical of course.) If it's quiet and spins easily it's pretty safe to assume everything is O.K. I pump in some marine grease every two or three saltwater dunks and it's worked good so far. My trailer is fairly new and it has the springs that show the grease pressure when pumped that is an advantage.

[Tim_Mattson]

Wheel Hub Assy

Jerry ,
I did trailer work for the Sorensens and saw some newer wheel hubs the past few years that come with a Zirk fitting right at the rear bearing.It makes greasing the back bearing easier but is tough to get to with tire still on.
They sell this beauty with the bearings pre-lubed and loaded,just remove and clean-up the old,then slide on the whole Hub with bearings and all.
These cost less that $40 bucks each ,so it doesn`t make sense if you want to save some time.
You need to count the lugs and know your inner bearing size,1 1/16`` is pretty common.....
New hubs will come with fresh studs and wheel bolts.
The Oil Bath looks cool too.....someday.
Then Nitrogn filled Tires that don`t go low in cold....or expand when hot.
Rear seals are so commonly bad ,it isn`t funny but they also are sometimes replaced with the wrong size.The stepped axles can mislead you on sizing if you don`t watch close.
I towed home a Dorsett one time that put on a Flaming lightshow......thought it was a fender rubbing and when I got home the wheel had burned a circular black mark on my EZLoader Fender.Axle nut was gone ,only the fender held the now totally loose wheel in place.Didn`t spin well when I jacked it up and I think it even fell over!
The 2 pc 1961 Seafair trailer was my other near catastrophy.
TimM

[Lootas1]

Thanks for info Tim. One of my sons once bought a boat many miles from home and started up the freeway when a bearing went out. He took a piece of heavy rope and greased it well and used it for a bearing to get him home. He always was an inventive kind of guy!