Trailer Bearing Maintenance "How to" video

[elcoyote]

Trailer bearing maintenance is the most important maintenance for a trailer and often the most overlooked. To help folks out a bit with understanding the basic process, we have uploaded a simple how-to-do-it video for those tackling this for the first time or are in need of a refresher. Enjoy!
http://www.youtube.com/watch?v=omLuXqwoRrA&feature=c4-overview&list=UUTvFXCjw_ChBoltTlghGfLg

 

[Kflash]

On the M416, I was probably the first in many, many years to have done it. With moderate use and not on a trailer that sees water (ie boat trailer), how often should one have to do this? Can one just repack the bearings and inspect the races from time to time?

 

[The Swiss]

Your timing could not be better, thanks. Checking bearings is the very next thing on the to-do-list for my Casita trailer!

 

[Martyn]

On the M416, I was probably the first in many, many years to have done it. With moderate use and not on a trailer that sees water (ie boat trailer), how often should one have to do this? Can one just repack the bearings and inspect the races from time to time?

For trailers used on road it is suggested that the bearings are checked and repacked every 12 months. As off road trailers can see some extreme conditions it should be done more frequently. Check your wheel bearings for excess play every time you use your trailer.

When repacking the original bearings check the bearings and races at the same time. Check for wear patterns, and areas that have darkened due to excessive heat. Run your finger over the bearings and races to check for gouges and sharp edges. If you find any of the above replace the bearing and race.

When you have the hub off check the spindle for signs of wear.

There is more information on bearing service here.

AT uses Timken bearings and races. Imported 1750 lb bearings do relatively well on off road trailers, but we have seen bearing failures on trailers with larger tires sizes. The quality materials and high tolerance levels used by Timken brings the probability of this occurrence into the single digits. With wheel bearings being the only major moving part on a trailers the bearings are worth the investment.

AT stocks Timken inner and outer bearing kits and inner seals. Next time you perform a bearing service, or if you want to carry a spare bearing kit, give us a call.

 

[ChaseN]

Trailer newbie here, so please don't flame me -

why is it that trailers need so much attention to their wheel bearings? I mean our trucks, which are typically thousands of pounds heavier, and see much more use and abuse, can go hundreds of thousands of miles without needing any attention to the wheel bearings. Why is it that trailer wheel bearings need checked and adjusted and greased every 6 months to a year? Makes no sense to me.

 

[elcoyote]

Trailer newbie here, so please don't flame me -

why is it that trailers need so much attention to their wheel bearings? I mean our trucks, which are typically thousands of pounds heavier, and see much more use and abuse, can go hundreds of thousands of miles without needing any attention to the wheel bearings. Why is it that trailer wheel bearings need checked and adjusted and greased every 6 months to a year? Makes no sense to me.

Very legitimate question and there are several reasons why. Here are a few:
Vehicle bearings are much larger in diameter and width and are rated for longer duty cycles between maintenance. It is not expected that you will put the same amount of miles on your trailer as you will on the vehicle however there are some heavy users here on the forum such as myself that will put 30-40K per year on a trailer. I service twice a year. While trailer bearings are smaller, they can when at capacity be carrying just as much if not more per wheel than your vehicle i.e. a 3500 lb axle has a load rating of 1750 lbs per wheel. Some Expo trucks approach 6000 + lbs, that is 1500 lbs per wheel with a much larger bearing.

Trailer bearing systems are also designed for a smaller tires in on road conditions. Most on road trailers utilizing a 3500 axle (1750 per wheel) are running tire sizes from 175/80R13 to 205/75R15 and hence the stress on the bearing is not as much as what we would expect for an AT trailer with 285/75R16 or 37x12.50R17 tire. This begs the question, why not simply go to a higher rated axle? The reason is hub bolt pattern availability. In the 3500 lb axle configuration we have ready access to 5/4.5, 5/5, 5/5.5 & 6/5.5. When we need 8/6.5 we use a 5000 lb system, unfortunately the other bolt patterns are not available in the 5000 lb config.

Frequency of use is another reason. Most trailers are used seasonally and spend most of the year parked. Over the course of a year, the surfactants can sepearate from the lubicants in grease resulting in a sticky mess that does not lubricate. Not changing the grease can result in bearing failure. There is at least one case I know of where a ExPo member purchased a new trailer that had been sitting in a warehouse for a couple of years. Within the first few hundered miles there was a bearing failure due to the breakdown of the grease.

I hope this helps answer your question.

We have good habits about checking the oil in our vehicle and the air in our tires. If you are towing a trailer, it is good to have the same pro-active habits about checking wheel bearings, air pressure and couplers.

 

[Martyn]

Sounds like Mario has been thinking about this as well. I wrote out my answer and didn't see that he'd replied already. As you can see my reasoning is slightly different from Mario's, but that is why we make a good team.

Bearing design; is a field of it’s own, bearings have to be designed to withstand thrust load, radial load, and shock load.

Vehicles wheel bearings are either selected or designed for the specific vehicle and its intended use. So there is a high degree of customization of the wheel bearings for individual vehicles.

Trailer bearings are general generic, selection is determined by the weight of the trailer.

Lubrication; Modern vehicle wheel bearings can be pre lubricated and permanently sealed, or the bearings are in an oil bath, or the bearings are splash lubricated.

Trailer bearings are lubricated by grease, the bearings are either hand packed or packed with a bearing greaser. (There are a few manufactures who make sealed oil bath bearings for trailers).

Construction: Bearings can be made from ball bearings or rollers. Ball bearings have less contact surface area allowing free movement and lower friction. Rollers have higher contact surface area, produce more friction and heat. Ball construction can transmit destructive shock load to the race due to the lower surface area and high pressure. Rollers distribute the shock load over a larger area and the shock force is reduced.

Vehicles tend to use ball bearings, trailers bearings are almost always rollers. Rollers are great for the constant shock loads that off-road trailers experience, but not so great for high speed road travel where they create friction and heat.

Quality: This is based on personal experience rather than anything empirical. I have seen trailer bearings fail after 500 miles, while others will be good for 100,000 or more. Trailer bearings are generally very inexpensive, and in my opinion the reason they are so inexpensive is that the material they are made of is questionable and the quality control is low or non existent. AT uses high quality Timken bearings for this very reason.

Installation: My experience with vehicle bearings is that the installation instructions are very specific and the bearings are pre loaded to a certain torque setting. Most bearing installations are done by trained technicians.

Bearing installation on trailers involve a certain amount of art as well as science. The pre load is done by feel rather than torque setting, and it is usually the owner who does the installation.

 

[Hilldweller]

... There is at least one case I know of where a ExPo member purchased a new trailer that had been sitting in a warehouse for a couple of years. Within the first few hundered miles there was a bearing failure due to the breakdown of the grease. ...

Yeah, that was me.
And thanks for showing me how to service bearings at Overland Expo, Mario. You and Martyn are a great resource and good friends to the community.

 

[Mark Harley]

Most new Vehicles use Unit or hub bearings that are sealed units and "NON SERVICABLE"
The bearings can be checked for run out or slop by jacking the vehicle up and checking for lateral play and looseness.
They will also let you know when they are about to **** THE BED by grinding while in motion.
ABS sensors tell us when a hub unit is shot too.

I just replaced both Hub units on my 2500HD crew. It was a simple job and took less than an hour each side.

 

[VanIsle_Greg]

The trailer bearings on my CDN M101 were replaced when I picked it up. Apparently the original owner (Canadian Military) and the 2nd owner took good care of it. The races were perfect and the bearings looked like they had less than a few hundred KM"s on them. I swapped the drums, so I ended up with new races and bearings, but I used the original bearings that came with the trailer (German IIRC vs. Chinese) as they were much nicer, kept the "offshore" ones for spares. I will replace with Timken next go round, good rep and widely available.

The bearings on the MilSpec trailers seem to be quite robust, but as stated above they sit for 90% of their lives (well mine does...sadly), so I can see at least yearly maintenance or semi annually at the least. I need to do a re-pack on mine after this trip this weekend.

Good thread. Below is from the CDN M101 manual, suggested maintenance/lubrication for the spindles is as noted..."Technicians shall lubricate wheel spindle assemblies once a year, at 12,000 km (7450 mile)
intervals, or after fording."

 

[Tooner]

I'm getting ready to clean & re-pack my bearings, great timing and a good refresher!! Thanks

 

[Cabrito]

This is a great PSA Thread.

I've been with friends and heard stories from friends where bearing failure caused major delays before, during , and on the way home from trips.

The absolute first thing I did when I purchased my little trailer was to inspect the bearings and races. Then I just went ahead and replaced them for peace of mind. I purchased spares to carry with the trailer. I did not replace the bearing race in either one, but perhaps I should at least inspect them a little closer.