Repacking Trailer Bearings - How Often?

[Custom Eyes]

Originally Posted by h8go4s

(1) The temperature difference between the hub and the water is so minimal and the volume of grease in the hub is so small that any vacuum generated is minimal.

(2) Bearing buddies are spring loaded to compensate for those temperature differences. The seal won't move in and out because the spring loading on the bearing buddies creates positive pressure inside the hub.

(3) The comparison with outboard prop shaft seals is not valid. Prop shafts are running underwater constantly and rotating at high speeds while doing so.

At the risk of repeating myself, I'll repeat myself and quote my previous response"

"I disagree. First, if your hubs are "hot", you have a problem. I check mine every pit stop and they are just slightly warm. Second, the purpose of the spring loading on bearing buddies is to maintain positive pressure inside the hub so water can't get in. You can't create a vacuum with properly maintained bearing buddies. Just grease the buddies enough to make sure the spring is compressed. Don't bottom it out, you will the be forcing grease past the rear seal. It's worked for me for thousands of miles and dozens of years on three different rigs."

1. See my experiment for you below. Ever feel how warm a hub with brakes on it gets??? And the less grease actually makes for more of a vacuum. A vacuum is pulled much easier on air than a semi-solid like grease.

2. See experiment again.

3. Your statement actually agrees with my point. Only debate would be the amount of water intrusion over given time.

At the risk of repeating MYSELF : " It's probably happened to you countless times, but you'd never notice it given the fact that most CS greases can hold 25-40% of their weight in water, so you'd never see free water in the hub, only slightly cloudy grease."


OK, I'm not going to argue this back and forth with you, so here's a real life experiment for you to try.

Next time you're pulling your trailer and everything is up to operating temp, when you get home, crack the front seal on the bearing buddy to equalize the pressure. Now let it sit and cool to ambient temperature. Especially if you have brakes on that axle, notice how the cap is sucked in from the vacuum after it cools. Next, wait until the next morning or a few hours later, and you'll see that the cap has more than likely returned to it's normal position with equal pressure on both sides. Once you do that and see for yourself, get back with us on the answer of how there is no vacuum, and how the heck did the pressure equalize in that system you think is so absolutely air tight?!

[T Mac]

If you are throwing grease despite not overfilling your bearing buddies... Do it.

On my 17' jet rig ...7 years of use now...I had the bearings repacked & resealed for the first time, yesterday.
I tow this boat to Texas and back (4000 miles round trip) and use it in salt bays during winter.
This year will be trip #4.

It was throwing grease out of the inside seals.
So it was time.

[Shellback]

Picked up a new to me rig. 2013 Alaskan 1600. I'm putting brakes on the trailer, and weighing whether I want to use bearing buddy's or a similar product. Cripes there's probably 1950 Ford's out there still running on their original front wheel bearings with dust caps. If I just use a standard dust cap and use a sealer when I install it, do you think I could get water intrusion through the rear seal due to this vacuum people are talking about?

[rickn]

Yes. The shape of the seals won't keep water out. The vacuum occurs when the warm hub is dunked and the grease contracts because of the temperature change.

[Custom Eyes]

Originally Posted by Shellback

Picked up a new to me rig. 2013 Alaskan 1600. I'm putting brakes on the trailer, and weighing whether I want to use bearing buddy's or a similar product. Cripes there's probably 1950 Ford's out there still running on their original front wheel bearings with dust caps. If I just use a standard dust cap and use a sealer when I install it, do you think I could get water intrusion through the rear seal due to this vacuum people are talking about?

Yeah, no guarantee to keep water out. Best defense is to assume it is going to happen and use the proper grease to neutralize it.

[Shellback]

I understand the theory of temperature change and a vacuum, but cars can have hot brake and drive through flooded streets at times, and it never seemed to be an issue with them. I've been driving over 50 years, and don't recall ever having to replace front wheel bearings on a car. I'm beginning to think bearing buddies are more of a gimmick, and actually may be the problem letting water in. If the oil bath hubs seal out water, why shouldn't a hub with a standard dust cap seal out water?

[Custom Eyes]

Originally Posted by Shellback

I understand the theory of temperature change and a vacuum, but cars can have hot brake and drive through flooded streets at times, and it never seemed to be an issue with them. I've been driving over 50 years, and don't recall ever having to replace front wheel bearings on a car. I'm beginning to think bearing buddies are more of a gimmick, and actually may be the problem letting water in. If the oil bath hubs seal out water, why shouldn't a hub with a standard dust cap seal out water?

Cars and other vehicles also get water intrusion. You generally don't see it because the water gets vaporized off from the heat. With all the stopping and having higher loads, auto bearings get much hotter. Think about it this way. If a standard bearing never got water or dirt intrusion, you'd never have to replace it like new lubed for life sealed bearings. I know in the 80's-90's I generally had to replace front wheel bearings on most cars within 100k miles. Now it's 200-300k miles, if ever, with sealed bearings.

And yes oil bath hubs get water intrusion also. Which is why most use a water soluble glycol oil in them, or a sulfonated oil. Water will readily mix right in with a w/s glycol base oil and disappear.

[GeorgeJr]

Originally Posted by boat nut

I'm in exactly the same situation with the trailer and miles and dunkings/year. I am a little leery about taking apart the wheels (with brakes now to make things more difficult) when there is no grease leaking from the bearing buddies or the rear seal, so like you and others, I just give a couple of squirts of grease until the front plate moves, a couple of times a year. I also jacked up and gave each wheel a quiet spin this fall. It seems ok, so will leave until next yer (year 3).

From Shorlandr owners manual:
http://www.midwestindustries.com/doc...rs%20Guide.pdf
Page 9 on repacking Bearings: Check the grease yearly not needed to repack unless contaminated or broken down. When repacking replace all seals.

Page 11 Recommended Lubricant... Note Greases need to be of the same base to avoid separations. If you change you must clean and repack with the new grease. Shorelandr uses a Over Based Calcium Sulfonate as the base and is very very good, but a bit harder to find. Get some and enjoy the anti corrosion properties if that is the type of trailer you have.

Brakes do add heat which will break down grease quicker. Doing maintenance is for some piece of mind, but do you replace air filters even if they look new? I've got plenty of equipment to maintain on our farm/home. I keep it simple as follows and noted my many already. For example a combine has a few moving parts. Lots of grease fittings to be greased. Some 25 hrs some 50 hrs... We mark them so we grease only as required because often we can't see the bearings or the grease to check the condition and need to make sure we get all of them. Some don't grease at all or once a year.. As long as the grease hasn't broken down its ok but running metal on metal... Yep quick way to end your day.

Grease today is Far Far better than the post whale lard of the past. If you feel better repacking every trip or every year that is your choice but we spend enough time getting ready to fish I'd rather go with proven methods of maintenance and enjoy more fishing.

Read and understand how your bearing buddy type system works. On Shorlandr trailers 1/8 inch believe is the amount the plate should be out with pressure on it from the spring. Do this when everything is cool so it can expand when heated and have grease avail when you dunk your trailer at the launch. Cool your axles some before launching. Stop and load everything up prior to launching will give the axle time to cool before you dunk. When you are driving stop and check with hand your tire temps and axle. Using a instant read gauge is great but your hand has been working for years and always with you I hope. If hot you have problems starting if warm your fine. I check every stop and even when I'm in a hurry to get the boat in the water. Before any big trip or first/end of the season always jack up and spin your wheels to check for brakes, bearing and tire issues. Also check for bearing play. Slight wiggle is ok but no more. If loose plan on re-greasing so you have parts ready. Tighten and see if it is still smooth. If loose then keep going with the repacking process.

Last boat trailer went about 30 yrs before one wheel started to spin rough. Pit on bearing was with about 30k miles at that point. Purchased 2 complete bearings and seal set and kept 2nd for a spare. Never needed 9 yrs later it new owner is going to go about 3k/year and going with same advice as of last year.

Remember brakes that are sticking will heat up a axle very fast and tires going bad will as well (cord/belt separation). That is why I check the tire and axle.

Keep your speed down... ST tires are normally rated for MAX speed at 65 MPH. Only Goodyear allows 10 more PSI to allow 10 more MPH but no more carry capacity to go faster than rated speed. As far as I'm aware they are the only ones to OK faster than 65 MPH but no faster than 75. Speed adds heat which causes everything to get warmer (tire warms rim, rim warms axle..). I've been passed by Many Many boats going faster than 75... I don't drive over my speed rated car tires (heck car can't even go that fast) not sure why you would do that with a trailer. I"ve seen a pop up trailer turn a surburan on its side in the ditch... Don't think your boat couldn't take your truck over. In a semi if I would get a blowout I keep on the gas till the vehicle is stable then slow down. Per Michelin tire company, I suspect that same holds true for boats and other trailers as well. NEVER SWERVE OR HIT BRAKES or you will find out too quick how much force you have when trying to decelerate F=MA even if you didn't study it in school.

Great question and hope this info helps ya. Looks like you are not that far away. PM me if you need any help with finding the right grease if you have a shorelandr.

Goodyear Marathon ST tire speed rating bulletin.
https://www.tirerack.com/images/tire...plications.pdf.