Not sure what I am looking at.. so I was driving back from the lake and noticed something pop off my trailer... new right away it was the little cap that goes on the hub. Figured get a new one, pop it back on. Problem is, the side that popped off, does not look like the other side... So first image is the side that popped off, the second image is the other side with and without the plastic cover.

See how the side that popped off is protruding a bit? And the other side that I took the cap off to compare is flush?

What does that mean? Do I need to get a new hub, new bearing buddies? This is an 07 Stratos trailer..

Thanks for the help in advance.

Straight off bearing buddy.. The Bearing Buddy 42201 II Bearing Protection and Lubricant keeps water and dirt out of the hub while internal pressure is always maintained at 3-PSI. The 42201 features a high quality, stainless steel construction for its internal parts and a triple chrome-plated barrel. This is the ultimate bearing protector with the added feature of "Auto Check: Visual Lubricant and Pressure Indicator." This updated version of Bearing Buddy has a spring loaded piston behind the Auto Check ring that pushes against the grease which generates pressure inside the hub to keep water out. If the lubricant is low, the blue Auto Check ring will recede until it is flush with the steel-retaining ring. Add a small amount of grease to move the blue ring outward about 1/8 -inch. It's that simple!
the center shiny cap pops out to allow you to access the grease fitting. You can buy replacement rubber caps. Hope this helps.

That helps,. so itr is supposed to be sticking out? So the one I did not lose the cap on was flush, thats the one that needs grease?

Yes

As you grease your hubs, the pressure of the grease will push on the plate that the grease fitting is connected to.
As the pressure of grease pushes the plate outward, the blue collar that sits on top of the plate, will also travel outward.

If the blue collar is flush with the outside of the hub, the hub needs grease.
If you see blue collar sticking out, the hub is good.

The “bearing buddy” is junk, get rid of it and pack your bearings like a man and put a little dab in the hub.

Every part of every trailer is junk. So what’s your point?

True enough lol.

Not the topic but I really like Dexter axles with the grease fittings on the end of the axle and it allows you to pump grease through the bearings.

Call me fortunate if you want but I had buddy bearings on my OKT trailer. In 30 years I never had a bearing problem. I always made sure the buddy bearings had the proper amount of grease in them. In 1985 when the trailer was built it would not have had the Chinese junk that I understand is out there today.

That grease fitting only allows grease into the hub, not directly to bearings.

I use oil filled hubs. Change the oil once a year and done.

I also have the dexter type on my 95 champion trailer, those let the grease in between the bearings where it should be.

you have to pack the assembly full of grease in the beginning so that when you grease with a gun you are pushing grease into the bearing and not air. also look for grease sepage. the assembly has to be full of grease to begin with.

I have seen an oil filled where a rock or something hit that plastic and knocked a hole in it....Oil leaked out. Not good.