Cobra Trailer Wheel Bearing Life

[Terry]

I believe wheel bearing failure on glider trailers are rare but would like to hear from others who have had trouble on the road with wheel bearings and at what age and mileage. I have a 26 year old Cobra trailer with about 35,000 road miles and planning a 3,000 mile cross country trip this summer. Bearings seem to be smooth and solid but concerned about age of the sealed grease. The trailer has been hangared most of it's life but has not been used for 3 years and considering replacing the bearings before the trip.

Terry Edmonds

[Joe Rodriguez]

The bearings are pretty cheap on Amazon. I just replaced mine. I did it for the same reasons you are describing. The bearing is a standard size used on a lot of those Polaris UTV axles. 

On Sat, Mar 14, 2026 at 8:47 AM Terry <t348...@gmail.com> wrote:

I believe wheel bearing failure on glider trailers are rare but would like to hear from others who have had trouble on the road with wheel bearings and at what age and mileage. I have a 26 year old Cobra trailer with about 35,000 road miles and planning a 3,000 mile cross country trip this summer. Bearings seem to be smooth and solid but concerned about age of the sealed grease. The trailer has been hangared most of it's life but has not been used for 3 years and considering replacing the bearings before the trip.

Terry Edmonds

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[Tom Watson]

Cheap insurance!

Sent from my iPhone

On Mar 14, 2026, at 11:52 AM, Joe Rodriguez <smoke...@gmail.com> wrote:



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[Mark Mocho]

I've worked on lots of trailers over the years including Cobra, Komet, Minden Fab and others. When I check bearings, the most common fault I see is lack of lubrication, or hubs and bearings with a mix of different greases. The best solution is to remove the hub and bearings, clean out ALL of the grease, repack the bearings with a good quality molybdenum wheel bearing grease and shove extra grease into the axle/hub cavity. You can't really go wrong with too much grease, but don't get too carried away. The problem with using different types of grease is that grease types often do not play well together and you can get a mix that sets up and acts more like soap. If the trailer sits immobile for several years, the grease can also "set up" and become kind of stiff. Once again, the solution is to clean it all out and repack the bearings every few years. It's a pain and kind of messy, but not as much trouble as finding yourself wandering the wilderness by the side of the road looking for a wheel that took off into the countryside.

I haven't heard of any problems with the Cobra sealed bearings (introduced in 1992), but I would be interested to hear from users that might have experienced a failure. I have never had to replace any of these. Problems seem to be associated with old-style tapered bearings and the seals on the inside of the hub. These problems nearly all involve old or insufficient lubricating grease, worn seals and incidents where the hub gets submerged (like in a flooded field) for extended periods. Tapered bearings are by far the most common style used on the majority of trailers I've seen. One sign that you are likely to have problems is if the dust cap on the hub is missing, or if it is the type with an accessible grease port, the rubber plug covering the hole in the cap is missing. This is a big red flag and should be addressed immediately.

[Charles Mampe]

I am assuming you have open taper roller bearings, not a sealed cartridge bearing.

Common failure is, sitting long periods and the oils separate out of the grease leaving clay and water immersion (mostly boat trailers).

While messy, cleaning and packing with fresh grease is easy to do. New grease seals are usually easy. The seals usually have a part number on them that can be cross referenced online or at an auto parts place.

I do not use a bearing packer, latex gloves and a can of grease works well.

Setting the nut torque is the only tricky part.

Cartridge bearings last a long time but can't be serviced. To replace usually requires a shop press. The retaining/axle nut has a torque value, just "making it tight" can kill a new bearing.

If you seal "oil" leaking out of a bearing, it needs attention. If the cap is missing, the bearing likely needs attention.

Jacking a wheel up off the ground, spin it, it should be smooth not gritty or loud. Wiggle the wheel, hands at 6&9, 12&6, there should be no play.

For Terry, I would clean and repack the bearings now, worth not having the headache on the road provided they are open taper roller vs. sealed cartridge.

[George Haeh]

Don't drive off with the brake on, too far and it's new shoes and bearings. 

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[Gordon Wingate]

Done that! I was able to find a place to get the brake shoes relined for $110. Bearings can be had for less than $50 on Amazon. New shoes from Cobra will cost you close to $300 with the current tariffs.

Gordon

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[Terry]

I didn't make it clear in my first post the bearings in my Cobra trailer are the sealed type. They seem to be fine but I will likely replace them anyway

Terry

[Charles Mampe]

As with any cartridge/sealed bearing assembly, you may need a press to remove the old bearing. Almost all have an internal snap ring holding them in, but usually a "light press" fit into the hub. Corrosion will make this worse.

Installing new, I usually put the new bearing in the freezer a few hours or longer. Clean up the hub bore and snap ring. I sometimes even heat the hub to 120*F+ (pretty hot to handle) and then drop the new bearing in until it's seated.

Your bearings may be fine based on miles, but sitting years never helps.