Why are three of my wheels running hot?

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I am not an expert nor mechanically/electrically inclined so this may be a dumb comment but...since the brakes are electrical could the one brake not be getting the correct amount of electricity required to fully engage the brake (loose/corroded connection?) on that brake? 
 
Locking up a brake with the wheel off the ground and spun by hand doesn't mean much. Any braking at all will stop the wheel pretty much dead in that scenario. Rolling down the highway is an entirely different situation.

It would be great if someone with a similar size trailer could measure the heat of their hubs. 175 degrees seems high for "normal", but maybe 150 is not? I dunno, but I would have guessed something more like 120 for normal running with occasional braking.
 
I guess the brake test was to determine if one wheel was not braking at all.  That would certainly explain what was happening.  I determined that the brakes are functioning to that wheel.  But I don't know if they are doing the same job.  The puzzling thing is that they were fine until I had the problem in KY and got the one wheel rebuilt.  Before that the wheels were the same temps and immediately after that, they were not.  That seems to support the suggestion that perhaps those linings got grease covered when the grease boiled out and are not grabbing as well.  I think I need to inspect the brakes on that wheel for glazing, etc., and then maybe adjust those brakes a little tighter and adjust the other three a little looser.  And see if that evens out the temperatrue discrepancy.  And confirms what the problem was.
 
Aren't the wheels on an axle and if so, wouldn't the brake on the wheel opposite the "cool" wheel on the same axle stop it in your brake test? Seems to me the obvious answer is that 3 of the brakes are doing all or more stopping (maybe more than they should if adjusted wrong or scored, etc.) or one brake is not doing much if any. I don't think your "brake test" was valid.

Frank
 
FrankNSharon said:
Aren't the wheels on an axle and if so, wouldn't the brake on the wheel opposite the "cool" wheel on the same axle stop it in your brake test?
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I believe the wheels rotate individually on each spindle.
 
FrankNSharon said:
Aren't the wheels on an axle and if so, wouldn't the brake on the wheel opposite the "cool" wheel on the same axle stop it in your brake test?
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I think if one wheel is not braking there would be pulling to one side.  I'm not sure if one brake can not work on an equal pressure hydraulic system.
 
Hope I didn't miss it, but have you tower the trailer with the /trailer Brake Controller disconnected.  If you do that and the Temps are the same that would prove conclusively that it is a braking problem.

If the temps are the same with the brake Controller disconnected then I would check the positioning of Brake Magnet on the cool wheel as well as the integrity of connections and wiring to it/them.  If it has dual magnets verify that both are good.
 
Looks like I am going to have a busy day tomorrow, checking out all the possible scenarios.  I bet that at least one of them solves the problem and explains what has been happening.  I did think about disconnecting the brake controller and see what happened but wasn't ready to drive ti without trailer brakes yet. 
 
I'm not sure if one brake can not work on an equal pressure hydraulic system.
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It's not hydraulic - this is an electric-magnetic trailer brake system, and the brakes on each wheel are independent.

A trailer won't show much pull if one just one wheel is braking less than the others - the tow vehicle and the other wheel's brake keeps it pretty much in line. A tail car with a technically-minded observer might notice an initial move towards one side or the other, though.
 
You may have a bad electrical connection going to the cool wheel, so it's not getting as much voltage as the others.  Power is related to the square of the voltage - drop the voltage by 10% and you'll get 20% less power. Drop it by 50% and you'll get 75% less power.

If you can't find any contamination on the brakes, the drum looks good, etc. get a couple of straight pins and push them into the brake wires after the last splice going to the magnets.  Put your voltmeter on the pins to measure the voltage, then pull the breakaway switch to send full battery voltage to the brakes.

Now repeat the test at one of the other wheels and see if there's a significant difference.

If you use small pins the insulation will self-heal when you remove them.  Or just put a dab of sealant over the pinholes.
 
Thanks for explaining about the voltage test.  It does make sense that reduced voltage would change the braking but I keep going back to when it happened.  The trailer is only three years old and sits very little.  Not a prime candidate for corrosion of connections, etc.  And everything was fine until the bearing blew in that wheel.  The temps were all consistant until that point so it makes sense to me that something happend then that is still keeping that wheel from braking properly.  Like when the grease got so hot and melted, that maybe it coated the brake shoe.  One of my friends told em that he always sands the surface of the brake lining when he has the hub open.  I'll know soon and can then decide which of the other tests to try.
 
Comer, You done the other 3 wheels yourself so it appears the that the one difference may be in how the brakes were adjusted. I would adjust the brakes on that wheel the same as the other 3 and see if it makes a difference.
 
Anything could have happened to the brake wiring and brake assembly when the shop worked on that other hub. Just because it isn't necessary to disturb the brake to do a bearing does not mean that nothing happened to it.

We might be barking up the wrong tree here, but its something that needs to be eliminated or confirmed in the diagnosis.

Another quick test is to disconnect the hot wire to one of the other brakes and see how that affects the hub temperatures. If the disconnected hub has temps similar to the "cool" one, that suggests braking is the heat/cool source rather than bearings.
 
I expected to have some test results today and worked quite awhile on the things that have been recommended.  Just as I got the wheel back on, my neighbor decided that he wanted to finish siding his house.  And he seemed to recall that I had offered to help him, some time back.  So, the test has been rescheduled until tomorrow morning.

I did take the wheel and hub off and tested the magnet with my test light.  When the brakes are activated in the truck, there is juice to the magnet.  I then cleaned up all the melted grease covering things (used a whole can of brake cleaner) and then I sanded the surface of the linings in case there was some glazing there.  Finally, I adjusted the brakes on just that one wheel so they should grab a little more.  I plan on taking it out to see if the wheel temperature has changed, relative to the others.  If there isn't much difference I am going to try disconnecting the brake controller and see how much the other wheels cool down. 
 
I'm back from another test run and there has been little or no change.  After adjusting the brakes on the cooler wheel and cleaning the surfaces of the linings and magnet, the temps are still about 50 degrees cooler than the others.  I see absolutely no braking problem and no pulling when driving or braking.  There is no tire wear and other than the temps, all if great.  Maybe I'm trying to fix for a problem that isn't there.  Except I still can't understand the temp difference and that makes me wonder if it is braking properly.  I know the brake is operational because it locks up when the emergency cord is pulled, it locks up when the brake in the truck is activated and it shows juice to the magnet when the truck brake is operational.  I just don't know how wheel it is braking but inspecting it shows no worn wires or connections, etc.  If I can't think of anything else I will probably be content that it works and not worry about the cooler temp.  I have a trip coming up in a couple of weeks that will test it.  500 miles or so of interstate driving.
 
Is it possible that the other 3 wheels brake magnets have current running through them at all times causing (perhaps) a slight brake drag which otherwise is unnoticeable??
 
The bearing races could still be the problem. I replaced wheel bearing a something a while back and was having a tough time getting the races out. I finally cleaned the inside if the hub and found two slots on the inside above the race to use to punch them out.
 
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