3500lb axles bad design
Probably most medium size trailers have the 3500lb axles and 10" brakes. The design of the spindles has little to no shoulder to locate the inner bearing. When I looked up the blueprints, I found that the spindle shoulder has a contact area against the ground surface of the bearing of about .020" and can be as little as zero using the print tolerances. That extremely small contact area can cause burrs, seal damage, loss of bearing adjustment and bearing alignment.
Today, I pulled and serviced all four hubs and found contaminated grease in two of them. The metal wearing away from the spindle contact area was the issue. The ground surface of a bearing is where it is to take the load, not the roughed in clearance radius.
To show you what I am talking about, in this photo is the blackened grease and a narrow band of metal which is the contact area that takes the lateral load of the trailer.
Here is a photo showing the result of the bearing radius carving its way into the spindle shoulder.
This photo shows the bearing with bluing so that the contact area can be found. Of course the bearing is on the spindle backwards for its photo op. The narrow dark blue band is the only support designed into this spindle. The lighter blue areas are where the roughed in radius is now locating the bearing.
I do not have an easy fix for this design fault. Short of replacing the axles with 5200lb units, all we can do is frequent bearing cleaning and repacking. For those that choose to use the grease fittings, just remember that the metal shards will be pushed to the outer bearing and the bearing adjustment still needs to be done frequently.
Here is a view of the metal shards I am talking about:
Today, I pulled and serviced all four hubs and found contaminated grease in two of them. The metal wearing away from the spindle contact area was the issue. The ground surface of a bearing is where it is to take the load, not the roughed in clearance radius.
To show you what I am talking about, in this photo is the blackened grease and a narrow band of metal which is the contact area that takes the lateral load of the trailer.
Here is a photo showing the result of the bearing radius carving its way into the spindle shoulder.
This photo shows the bearing with bluing so that the contact area can be found. Of course the bearing is on the spindle backwards for its photo op. The narrow dark blue band is the only support designed into this spindle. The lighter blue areas are where the roughed in radius is now locating the bearing.
I do not have an easy fix for this design fault. Short of replacing the axles with 5200lb units, all we can do is frequent bearing cleaning and repacking. For those that choose to use the grease fittings, just remember that the metal shards will be pushed to the outer bearing and the bearing adjustment still needs to be done frequently.
Here is a view of the metal shards I am talking about:
